2. Review of literature chapter-! ^view of Citerature

REVIEW OF LITERATURE

2.1 Behavioral and neuropharmacology:

The latter part of the twentieth century has been hallmarked by unprecedented advances in our understanding of neuroanatomy and the role that neurological processes may play in mental disorders. Neurobiological processes have been increasingly implicated in both the etiology and the treatment of substance-use disorders. These developments have made it necessary for those working in the field of addiction to have a functional understanding of neurobiology that would not have been necessary even 30 years ago. (Brick and Erickson, 1998)

Yet many practicing clinicians lacking a background in neurobiology and existing literature in this area is often written in a manner that is perplexing and inaccessible to the layperson, rendering self-education a daunting prospect. Clearly there is a need for the complex processes of neurobiology to be teased apart and explained in a way that is lucid and understandable, providing essential information without overwhelming or intimidating the learner. (Brick and Erickson, 1998)

Neuropharmacology is a branch of neuroscience involving the study of drugs that alter the nervous system and its functioning, specifically within the brain. The goal of neuropharmacology in general is to understand the basic functioning of impulses and signals within the brain in order to discover ways in which drugs can be used to treat neurological disorders and drug dependence. There are two branches of neuropharmacology: behavioral and molecular. (Meyer and Quenzer, 2004)

Behavioral pharmacology is now over 3 decades old. In 1955 Peter Dews published his article "Differential sensitivity to pentobarbitol of pecking performance in pigeons depending upon the schedule of reward." This epoch-making study, whose implications have yet to be fully fathomed and emerged, then soon after the efforts by many scientists provided a headwater of principles and research methods that remain in the mainstream of behavioral pharmacological investigation. But these proximal historical details obscure the distal, but deeper influences. The two disciplines whose confluence yielded behavioral pharmacology, namely the experimental analysis of behavior and pharmacology, have a common methodological origin in the classical physiology of Claude Bernard (1957). (Barrett et al., 1977)

A Study of the (Behaviotir(d andO^europharmacotogicaC effects of some iiuGgenous ptdnts. 6 Cfiapter-2 ^view of Citerature

This has been emphasized by Travis Thompson (1984) in his retrospective review of Bernard "An Introduction to the Study of Experimental Medicine" wherein he says: "The experimental analysis of behavior has typically had its academic home in the discipline of psychology. Paradoxically, the experimental analysis of behavior shares much more with the tradition of Claude Bernard than it does with those of Wundt or Freud. Indeed, if a 19* century progenitor of contemporary behavior- analytic theories were to be identified, it would be Bernard and not, as is often claimed, James or Pavlov. James's pragmatism and Pavlov's reflexology were peripheral to the meta-theoretical and theoretical foundations of modem behavior- analytic theory and practice." And, as said elsewhere: "The animal chamber and the cumulative recorder, as ingenious as they are, are direct descendents of the dissecting table and the smoked drum" (Barrett et al., 1977)

The experimental analysis of behavior has provided orderly and repeatable data on the actions of individual organisms. The data are subject to the most compelling visual display as well as detailed quantitative scrutiny. So it was with physiological investigation of organ and tissue systems. Consideration of the axiom that behavior is a biological property of organisms, coupled with the orderly data that can emerge from an appropriate behavioral analysis leads one to consider the significance of the study of the effects of drugs on behavior, or, more precisely, drug- behavior interactions. This reasoning, however, is both glib and formal and requires a more careful consideration of what might be termed the causal structure of the field of investigation. That is, the relationships and their directions holding between variables of one class, say pharmacological, and variables of another class, say behavioral. This causal structure is reflective of the rationale and methods for investigation. It constitutes the texture of functional relations and in a sense is descriptive of the consequences maintaining the behavior of the investigator. (Barrett et al., 1977)

One of the most general "covering laws" of behavioral pharmacology is the notion of rate dependency, (or rate constancy, if you prefer), i.e., that the rate of responding is an important determiner of a drug effect. Again, the effects of a drug on behavior are explained by reference only to a behavioral variable rate. A large variety of experiments and observations has been interpreted in the context of this principle. It has been questioned from several quarters; but it could be argued that for better or worse, it is, or has been, the only general integrative principle in behavioral

Jl Study oftfie (BeBavhuraf and ^europfiarntacolbgicaC effects of some indigenous plants. 7 Cfiapter-2 §(fview of [iterature # I pharmacology. But perhaps things are not all that bleak. Through vigorous and carefiil experimental analysis, salient variables and functional relations at the behavioral level have emerged that could provide for effective prediction and interpretation of drug- behavior interactions without the necessity to engage in shifts in levels of analysis. An example is the investigation of the stimulus properties of drugs which has evoked principles of stimulus control in the interpretation and classification of drug effects on behavior. (Barrett et al., 1977) The questions arise as to the relations between behavioral and phar­ macological variables. Thus: "What does a drug do to behavior?"; "What variables control these effects?"; "What do the effects on behavior tell us about the mechanism of action of the drug?" and, "What do the drug effects tell us about behavior?" The answers to such questions will depend minimally on what is meant by behavior, entailing an entire philosophical and methodological approach. Likewise, "mechanism of action" is in itself an ambiguous phrase to which one might respond with behavioral, physiological, biochemical or even molecular relationships. Consider the practice of describing the behavioral effects of drugs in such heterogeneous reductive modes as alterations in emotional, motivational or perceptive states, excitatory or inhibitory processes and the like. However, the experimental analysis of behavior, as manifested in behavioral pharmacology, has eschewed these kinds of expressions and has focused upon functional relations wherein changes in behaviors (e.g., key pecks, lever presses, verbal responses) are expressed in terms of such directly manipulatable variables as (1) schedule arrangement, (2) rate of responding, (3) consequences, (4) context, (5) drug history, and (6) behavioral history. Thus, answers to the question "What does a drug do to behavior?" are, first of all, generally constrained to statements about relative probabilities of actions and their distributions in time. This is in conformity with the old pharmacological principle that drugs do not confer new physiological, and by extension, behavioral properties or processes; they can only modify, i.e., enhance, reduce, or alter the frequency or pattern of a given fiinction. However, physiological or behavioral changes may possibly emerge from the presence of new combinations of molecular structures in which the drug participated directly or indirectly as, for example, by agents that alter genetic mechanisms. (Barrett et al., 1977)

Jl Study of the (BehavburaC andtN^eurofharmacofbgiad effects of some iruRgenous plants. 8 Chapter-2 ^view of Citerature

The six variables cited earlier are said to control the effects of drugs on behavior; that is, changes in behavior are functions of control rate, schedule arrangement, etc., separately, or in interactive combination. In this analysis, the drug can be looked upon as simply another environment or historical manipulation. This is perhaps most clearly exemplified by the study of the stimulus properties of drugs. These investigations demonstrate that, like other environmental events, drugs may act as reinforcing, punishing, eliciting, or discriminative stimuli. Such studies have both basic and applied value for the classification of drugs and for extensions of the principles of stimulus control gained through the experimental analysis of behavior in the absence of drugs. (Barrett et al., 1977)

The behavior analyst manipulates environmental variables with the ultimate consequence of developing a systematic, functional account of behavior. Be cause the imposition of a drug may be treated as another class of environmental manipulations, as suggested earlier, it follows that this manipulation might prove useful for the analysis of behavior. This aspect of behavioral pharmacology has not received the attention it deserves, yet for behavior analysts it should provide one of the most compelling rationales for the investigation of drug-behavior interactions. Drug effects can enlighten our understanding of behavior as well as reveal our naivete. As an example of the latter, punishment is usually defined as a consequence of responding that suppresses responding. Certain drugs diminish the suppressive effects of punishing events, an important effect in the screening of putative anxiolytic agents. Yet as shown, suppressive effects of some events, e.g., time outs or brief stimuli associated with periods of non reinforcement are not reduced by the usual anxiolytics. Just as that of "all that glisters is not gold," "all that suppresses is not punishment," at least from a pharmacological perspective. (Barrett et al., 1977)

The specter of heterogeneous reductionism gestates in questions of the form: "What do the mechanism of action of drugs tell us about their effects on behavior?"; or "What do behavioral effects of drugs tell us about the mechanism of action of drugs?"; and, perhaps most fundamentally: "What do the mechanisms of action of drugs tell us about the mechanism of actions of behavior?" (Barrett et al., 1977)

^ Stwfy of the (Befmviowd and O^europhaTmacoQig^C effect of some indigenous plants. 9 Cfiapter-2 Iff view of Citerature « » As mentioned earlier, classical pharmacology essentially shared its methods and levels of analysis with classical physiology. Following the views of Claude Bernard, neither science could have been said to be reductionistic in the heterogeneous sense. But modem physiology and pharmacology share in the general fund of biological explanation of which there are at least five aspects: (1) biochemical/biophysical; (2) physiological (i.e., organ and tissue function); (3) morphogenic developmental; (4) behavioral-environmental; and (5) species adaptation and evolution. (Barrett et al., 1977) 2.2 Various behavioral and neuropharmacological disorders: Mental dysfunction is defined as a disturbance or defect, to a substantially disabling degree of perceptual interpretation, comprehension, reasoning, learning, judgement, memory, motivation or emotion. The term 'mental dysfunction' is used to describe condition that cause individual to have disturbed thinking, behavioral abnormalities, mood swings and cognitive disorder. However, mental dysfunction is often associated with a permanent change in function such as acquired brain injury following an accident or due to a development delay. With mental dysfunction, individuals are likely to have difficulty in a number of areas such as decision-making, reasoning, comprehension, memory, judgment and emotional control (APA, 2000).

Jl Study of the ^ehaviowdaru£0<^ewoffiaTrMCo(6g^effecU of some ituGgenous plants. 10 Cfiapter-2 §!jview of Citerature

Mental dysfunction Abnormal behaviour in childhood Cognitive disorders Psychological disorders related to Substance related disorders Schizophrenia and other psychotic Mood disorders Anxiety disorders Somatoform disorders Factitious disorders Dissociative disorder Sexual and gender identity Eating disorders Sleep disorders Impulse control disorders Adjustment disorders Personality disorders Mental retardation Neurodegenerative disorders Figure 2.1: Various behavioral and neuropharmacological disorders (APA, 2000)

A Study of the (BefmviouraCamf^europliamacolbgicaCejfects of some indigenous plants. Cfiapter-2 ^view of fiterature

2.2.1 Cognitive dysfunction: Elucidation of the physiology mechanisms underlying learning and memory remains perhaps one of the greatest challenges facing the neuroscience communication today. One of the significant advances in the past two decades in terms of advanced understanding of learning and memory, is the discovery and elaboration of phenomenon called long term potentiation (LTP) that presumably represent neural correlates of learning in intact animal. Bliss and Lomo first described LTP in the anesthetized rabbit hippocampal formation in vivo. They found that a brief high- frequency electrical stimulus of perforant path axons in the denate gyrus evoked an increase in synaptic excitability that lasted for days to months. LTP was initially thought to be unique to the hippocampus; however, it has been now reported in many other brain regions of the vertebrate nervous system as well, including the neocortex, the limbic forebrain, the visual motor, somatosensory, coagulate, pinform, olfactory and ganglion. In the majority of studies LTP, has been reported a excitatory synapses N-methyl D-aspartate (NMDA) receptor plays an major role in the induction can be divided in to NMDA receptor dependent LTP, and NMDA receptor - independently LTP Non -NMDA excitatory amino acid (EAA) receptor may be involved in the induction of certain kinds of hippocampal LTP. (Kulkami and George, 1999)

Patients with mild forms of dementia and age-related memory impairment have just begun to benefit from pharmacotherapy developed over the last several years. Different classes of drugs have been tested for this indication including psychostimulants, anitcoagulants, vasodilators, hyperbaric oxygen, hormones, nootropics, cholinomimetics, monoaminergics and neuropeptides for the treatment of this condition. Recently, other drugs have also been proposed including neurotrophic factors, phosphatidylserine, angiotension converting enzyme (ACE) inhibitors, calcium channel blockers, acetyl-L-camitine, xanthine derivatives, anti-inflammatory agents, aluminum chelate agents, and D-cycloserine. Some of these approaches include the development of single molecular entities that combine activity as cholinesterase inhibitors, muscarinic cholinergic M2 receptor antagonists, nicotinic acetylcholine receptor agonists, a-2-adrenergic agonists, or monoamine oxidase inhibitors.

A Study of the (BelmviouraC and ^{eufopharrnacofosicaC effects of some indigenous plants. Cfiapter-2 ^view of Citerature < I A wide variety of clinical syndromes can manifest cognitive or memory dysfunction. These include head trauma, cerebrovascular accidents, convulsive disorders, nutritional deficits, drug-associated toxicity, etc. Although collectively these entities contribute significantly to the overall amalgamation of known memory disorders, by far the primary disease entity targeted by pharmaceutical research is Alzheimer's disease (AD). AD, which represents the most common form of dementia among individuals over 65 years of age, is now the third most expensive health care problem in the U.S. exceeded only by cancer and cardiovascular disease. It currently affects approximately 4 million Americans and imposes an annual economic burden estimated at between $80 and $100 billion. This devastating degenerative condition also inflicts an enormous emotional toll on patients, family members, and caregivers. As the geriatric population inexorably increases, the numbers of AD patients may increase to epidemic numbers (i.e., in excess of 9 million) by the middle of the twenty first century. An additional concern of older adults is the perception that memory loss occurs as a natural result of aging. This apprehension has contributed at least in part to the enormous increase in sales of over the counter remedies and homeopathic products with claims of memory-enhancing properties. This demand from a large and ever increasing elderly population also has provided the basis for a rising interest in the development of pharmacological agents, not only for the treatment of AD, but also, for the much more common, mild cognitive decline associated with normal, non- disease aging (Green, 1995). A measurable decline in cognitive function can occur as a part of healthy aging in humans, which begins at some point after the fifth decade of life. The changes observed in typical (nonpathologic) aging are manifested primarily as mild deficits in declarative memory which are thought to result as a consequence of a reduction in the speed of central processing necessary for encoding and retrieval of information . Mild memory deficits that exceed those associated with normal aging, have been referred to as "benign senescent forgetfiilness" and "age associated memory impairment" (AAMI). Recent evidence suggests that patients with AAMI have an increased risk of developing dementia, a finding that has generated considerable concern and provided the impetus for rigorous investigation. (Morris et al., 1991; Green, 1995)

A Study ofttie (BeRaviouraC and ^eufopharmacologiccd effects of some indigenous plants. 13 Chapter-2 ^view of Citerature •= Nootropics are a class of psychotropic drugs that enhance learning, acquisition and reverse learning impairments in experimental animals. The term 'nootropic' was introduced to describe a group of drug that has ability to improve brain mechanism postulated to be associated with mental performance. Nootropics exert their action by- facilitating flow of information between the cerebral hemispheres and enhancing resistance of brain to physical and chemical assault. They lack of sedative, analgesic or neuroleptic activity. The chemical structure of prototype nootropic, Piracetam is a derivative of GABA (Stahl, 1998).

'Nootropics' are a group of compound that is of intense current research. These are a group of compound of diverse chemical composition and biological function that allegedly facilitate learning and memory or overcome natural or induced cognitive impairments. Nootropic not only postpone or reverse "normal" brain aging but could even make 'normal' brain work better.

The concept and definition of a "nootropic drug" was first proposed by C.E. Giurgea in 1972. The term "nootropic" in Greek means "acting upon the mind". Giurgea derived the term "nootropic" from the words "noos"= mind and "tropein"= towards. Main features in defining a nootropic are:

• The enhancement of learning acquisitions as well as the resistance of learned behaviors to agents that tends to impair them.

• Partial enhancement of the general resistance of the brain and particularly, its resistance to physical injuries induced by convulsion, hypoxia and chemical toxicosis.

• The facilitation by interhemispheric flow of information.

• The increase in the efficacy of the tonic corticosubcortical control mechanism.

• The display of above mentioned activities by selective functional impact on higher integrative telencephalic mechanisms.

The nootropics or "metabolic enhancers" are drugs that do not interact directly with any specific neurotransmitter system.

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Classification of nootropics;

Nootropics

^f \f Metabolic Enhancers Cholinergic Activators e.g. Hydergine, Vinpocetine e.g. Huperzine A and DMAE and Bifemelane \' Cholinergic/Metabolic Enhancers e.g. Racetam Derivatives

Figure 2.2: Classification of nootropics

a) Metabolic enhancers:

Hydergine is considered to be one of tiie most important "smart drugs" available today. It is called the ultimate smart pill. Hydergine is tlie name of a group of drugs known as ergoloid mesylates. It is a mixture of three hydrogenated ergot alkaloids i.e. dihydroergocomine, dihydroergocristine, dihydro-a-ergocryptine and dihydro-p-ergocryptine (Nandy and Schneider, 1978). Hydergine acts in a number of different ways to enhance mental capabilities and slows or regresses the aging processes in the brain. It causes increased protein synthesis in the brain and leads to reduced accumulation of lipofuscin, increased quantities of blood and oxygen delivered to the brain, improvement of memory, learning and intelligence. It is an antioxidant and thus protects the brain against the damage (Nandy and Schneider, 1978; Saletu and Grunberger, 1985). Vinpocetine is derived from periwinkle plant. It is a derivative of vincamine which increases cerebral blood flow and production of ATP for cellular energy. Vinpocetine, when taken regularly allows the brain to make better use of oxygen and glucose and thus improve its functioning (Rischke and Krieglstein, 1991; Branconnier, 1983; Yamamoto and Shimizu, 1987).

Other metabolic enhancers include bifemelane, idebenone, indeloxazine and MCI-2016. They have protective effects against cerebral damage due to oxygen deprivation and are useful in the treatment of hypoxia, a state in which memory and learning abilities are impaired. They increase cerebral blood flow and supply of oxygen and glucose to the brain cells (Tobe et al., 1983; Cheng and Tang, 1998).

Ji Study oftfie (BefiavhuraC and T^eurxtpharmacofbgicaC effects of some indigenous ptdnts. 15 CfiapUr-2 %pview of Citerature I I b) Cholinergic activators: Huperzine A is an alkaloid obtained from Huperzia serrata. It is a potent AChE inhibitor. It blocks the depletion of ACh in the brain and has a protective effect on the cells of the brain. It promotes growth of nerve dendrites and also protects neurons against glutamate-induced excitotoxicity. Due to these effects it serves as a nootropic in improving memory and is also useful in AD (Geib et al., 1991; Xiong and Tang, 1995; Sergio, 1988). Dimethylaminoethanol (DMAE) is a precursor of ACh. It promotes neurological processes which result in increased intellectual capacity, increased learning capability, increased short and long term memory capability, concentration, focus and alertness (Casey and Denney 1974; Manetti et al., 2000)

c) Cholinergic / metabolic enhancers:

Pyrrolidinone / racetam antiamnesics:

Pyrrolidinone nootropics are derivatives of 2-oxopyrrolidineacetamide. The most representative and widely intentional compounds (Mondadori, 1996) of this class are piracetam, pramiracetam, oxiracetam, aniracetam, rolziracetam, etiracetam, nefiracetam, nebracetam, cebracetam and fasoracetam/NS-105. The members of this class share the property of reverting amnesia induced by scopolamine, electroconvulsive shock and hypoxia. They show an overturned U-shaped dose- response curve (Yarbrough and Pomara 1985). Piracetam, pramiracetam, oxiracetam and aniracetam are the four main commercially presented "racetam" nootropics (Tacconi, 1986), all of which share a pyrrolidinone nucleus. The racetams are closely related in structure to the amino acid pyroglutamic acid (2-oxo-pyrrolidine carboxylic acid) and differ only in the side chain. These nootropic agents are among the pharmacological safe drugs (Watabe et al., 1993).

Piracetam and its analogues have been in use for many years as "memory enhancers". Piracetam, the first nootropic agent to be identified, was in the search for an analog of GABA that would be competent of crossing blood brain barrier. It is a cyclic relative of GABA. It is an intelligence booster and a CNS stimulant with no known toxicity or addictive properties. (Watabe et al., 1993; Gouliaev et al., 1995)

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Piracetam-like nootropics:

Piracetam properties were disclosed in 1967 and this stimulated the design and synthesis of a large number of structurally related molecules that were found to be endowed with a similar pharmacological profile. This class of cognition enhancing drugs is often referred to as nootropics. Like the cognition enhancers of the first generation, piracetam-like nootropics can also reverts amnesia induced by scopolamine and other amnesing drugs, electroconvulsive shock and hypoxia with an unknown mechanism. This has been a major problem in accepting them as cognition enhancers, even though some of them have been found effective in clinical trials, show excellent tolerability and safety and, in some countries, have been used or are currently in development to treat cognitive disorders (see table 2.1). (Gouliaev and Senning, 1994)

Table 2.1: Piracetam-like cognition enhancers (nootropics): Drugs available or in development: 1 UJ'Uy - ^^''"'iP'''"bi ug coilt's Loiu|>anv kearol launch |

Piracetam UCB-6215 UCB 1973

Oxiracetam ISF-2522 ISF 1987

Aniracetam Ro-13-5057 Roche 1993

Pramiracetam CI-879 Wamer-lambert 1993

Nebracetam WEB1881FU Boehringer Ing Awaiting approval

Nefiracetam DM-9384 Daiichi Seyaku Awaiting approval

Fasoracetam NS-105/LAM-105 Nippon Shinyaku Phase III

Mechanism of Action In general, piracetam-like nootropics show no affinity for the most important central receptors (Ki > 10 mM). A modest affinity for muscarinic receptors is shown by aniracetam (Ki = 4.4 mM) and nebracetam (K, = 6.3 mM). Nefiracetam is the only one showing affinity in the nanomolar range (Ki = 8.5 nM on the GABAA receptor). As a consequence, they do not seem to act on any well-characterised receptor system, although modulation of most central neurotransmitters, in particular acetylcholine and glutamate has been reported. Neurotransmitter modulation could be due to

A Study of the (BehaviouraC and TieuropharmacobgicaC effects of some indigenous plants. 17 Cfiapter-2 ^view of Citerature •=—:— » interactions with ion channels: indeed this has been one of the mechanisms proposed to rationalise activity of some piracetam-like compounds. (Eid and Rose, 1999) A great deal of different biochemical and behavioural findings has been presented for piracetam-like nootropics, but so far, a common molecular mechanism of action is not indicated. On the other hand, generalisation is made difficuh by the fact that, quite often, piracetam-like nootropics do not share the same behaviour in many biological assays. Nevertheless, attempts to find common properties in the class have been made. On the basis of the finding that memory enhancing effects are steroid-sensitive, it has proposed that nootropics exert a modulatory action on protein synthesis. Protein kinase C (PKC) activation as well, could be a general mechanism of action of cognition enhancing compounds, as appears from studies on oxiracetam, aniracetam, and nefiracetam. (Gouliaev and Senning, 1994) Very recently, based on the effect of piracetam on the fluidity of mouse brain membranes, it has proposed that cognition enhancing properties of piracetam can be explained by their effect on brain membrane properties, in particular by modification of membrane-located mechanisms of central signal transduction. However, none of these hypotheses have, so far, gathered general consensus. It can be concluded that, thirty years after the identification of piracetam, a unifying hypothesis on the mechanism of action is still lacking and that this class of cognition enhancers, despite chemical similarity and close pharmacological profile, uses an amazing variety of molecular mechanisms to produce the final nootropic effect. (Nikolaos et al., 2002) 2.2.2 Depression: Mood changes (feeling of happiness and sadness) are part of our daily life. When reaction to these situations becomes extreme, that leads to a clinical condition, called depression and mania. The common symptoms of mental depression are in case of endogenous depression, motor retardation. The patient suffers from a showing down of his physical and mental process. He lacks interest in his surroundings. His thinking capacity and ability to concentrate are greatly impaired. (Dandiya and Kulkami, 2002)

^ Sttufy of the

Depression may be classified according to the type of symptoms; etiology; predisposing emotional characteristic; or time of life when the disorder occurs. From the time of view of drug treatment, depression may be classified in to:

1 Reactive depression (exogenous).

2 Endogenous depression.

Depression induces both quantitative and qualitative modification of memory. The former deficit is most evident in tasks that require sustained effort and elaborate processing. By contrast, information processing that can be accomplished automatically is generally unimpaired. This suggests that depression produces its quantitative effect on memory and cognition by interfering with a global cognitive resource allocated to a given task.

In addition to this quantitative effect, depression selectively biases memory toward negative aspects of the past, interacting in two independent, though complementary, and ways: depression increases the accessibility of negative memories to consciousness and accentuates the negativity of these memories. A viscous circle can therefore be established: depression induces the recollection of negative memories. Which in turn aggravate depression on memory has been mainly accounted for in terms of mood congruity. This phenomenon refers to the fact that depressed patients have a better recall of negatively than positively valence information; that is; they have a better recall of information whose affective valence is congruent with depressed mood. These quantitative and qualitative modifications are concern explicit memory, but not perceptual priming. In accordance with the hypothesis that emotions interact directly with strategic, but not automatic, processes, these results suggest that depression biases memory about past only when conscious, intentional recollection of information is required.

2.2.3 Anxiety disorders: The less pervasive psychiatric disorders include conditions formerly termed psychoneuroses, which currently are viewed as anxiety-associated disorders. The ability to comprehend reality is retained, but suffering and disability sometimes are severe. Anxiety disorders may be acute and transient, or more commonly, recurrent or persistent. Their symptoms may include mood changes (fear, panic, or dysphoria) or limited abnormalities of thought (obsessions, irrational fears, or phobias) or of

Jl Study oftfie (BeRaviouraC and ^europhamacotogical effects of some indigenous ptdnts. Cfiapter-2 ^view of Citerature

behavior (avoidance, rituals or compulsions, pseudoneurological or "hysterical" conversion signs, or fixation on imagined or exaggerated physical symptoms). In such disorders drugs can have beneficial effects, particularly by modifying associated anxiety and depression to facilitate a more comprehensive program of treatment and rehabilitation. Antidepressants and sedative-antianxiety agents are commonly used to treat anxiety disorder. (Baldessarini, 1999)

The antipsychotic, antianxiety, antimanic, and antidepressant drugs have effects on cortical, limbic, hypothalamic, and brainstem mechanisms that are of fundamental importance in the regulation of arousal, consciousness, affect, and autonomic functions. Physiological and pharmacological modifications of these brain regions may have important behavioral consequences and useful clinical effects regardless of the underlying cause of any mental disorder. The lack of diagnostic or even syndromal specificity of most psychotropic drugs tends to reduce the chances of finding a discrete metabolic correlate for a specific disease conceived simply on the actions of therapeutic agents. Finally, technical problems in studying changes in brain metabolism in vivo or the postmortem chemistry of the human brain are formidable. (Baldessarini, 1999)

In summary, there is no definitive link between discrete biological lesions and the pathogenesis of the most severe mental illnesses (other than delirium and the dementias). Even without such a link, we can provide effective medical treatment for psychiatric patients. It would be clinical folly to underestimate the importance of psychological and social factors in the manifestations of mental illnesses or to overlook psychological aspects of the conduct of biological therapies. (Baldessarini, 1999)

Pharmacotherapy of anxiety:

Anxiety is a cardinal symptom of many psychiatric disorders and an almost inevitable component of many medical and surgical conditions. Indeed, it is a universal human emotion, closely allied with appropriate fear and presumably serving psychobiologically adaptive purposes. A most important clinical generalization is that anxiety is rather infrequently a "disease" in itself Anxiety that is typically associated with the former "psychoneurotic" disorders is not readily explained in biological or psychological terms; contemporary hypotheses implicate overactivity of adrenergic

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systems or dysregulation of serotonergic systems in the CNS. (Stein et al., 1998 Laurence and Keith, 2008)

In addition, symptoms of anxiety commonly are associated with depression and especially with dysthymic disorder (chronic depression of moderate severity), panic disorder, agoraphobia and other specific phobias, obsessive-compulsive disorder, eating disorders, and many personality disorders (Boemer and Moller, 1999; Liebowitz, 1993). Sometimes, despite a thoughtful evaluation of a patient, no treatable primary illness is found, or if one is found and treated, it may be desirable to deal directly with the anxiety at the same time. In such situations antianxiety medications are frequently and appropriately used. (Mendels et al., 1986; Laurence and Keith, 2008)

Currently, the benzodiazepines and the SSRIs are the most commonly employed medicinal treatments for the common clinical anxiety disorders. Some high-potency benzodiazepines (alprazolam, clonazepam, and lorazepam) are effective in severe anxiety with strong autonomic overactivity (panic disorder), as are several antidepressants, as discussed above. For generalized or nonspecific anxiety, the benzodiazepine selected seems to make little difference (Rickels et al., 1993). In the elderly or in patients with impaired hepatic function, oxazepam in small, divided doses sometimes is favored due to its brief action and direct conjugation and elimination. Benzodiazepines sometimes are given to patients presenting with anxiety mixed with symptoms of depression, although the efficacy of these agents in altering the core features of severe major depression has not been demonstrated. The most favorable responses to the benzodiazepines are obtained in situations that involve relatively acute anxiety reactions in medical or psychiatric patients who have either modifiable primary illnesses or primary anxiety disorders. However, this group of anxious patients also has a high response rate to placebo and is likely to undergo spontaneous improvement. Antianxiety drugs also are used in the management of more persistent or recurrent primary anxiety disorders; guidelines for their appropriate long-term use for such disorders are less clear (Laurence and Keith, 2008; Liebowitz, 2002).

Although there has been concern about the potential for habituation and abuse of benzodiazepines, some studies suggest that physicians tend to be conservative and may even under treat patients with anxiety. They may either withhold drug unless A Study oftBe ^ehaviouraC andtKeuropharmacoCogicaC effects of some indigenous plants. 21 Cfiapter-2

symptoms or dysfunction are severe, or cease treatment within a few weeks, with a high proportion of relapses. Patients with personality disorders or a past history of abuse of sedatives or alcohol may be particularly at risk of dose escalation and dependence on benzodiazepines. Benzodiazepines carry some risk of impairing cognition and skilled motor functions, particularly in the elderly, in whom they are a common cause of confusion, delirium (sometimes mistaken for primary dementia), and falls with fractures. Risk of fatality on acute overdose of benzodiazepines is limited in the absence of other cerebrotoxins, including alcohol. (Laurence and Keith, 2008; Liebowitz, 2002)

A particularly controversial aspect of the use of benzodiazepines, especially those of high potency, is in long-term management of patients with sustained or recurring symptoms of anxiety (Laurence and Keith, 2008; Liebowitz, 2002). Clinical benefit has been found for at least several months in such cases, but it is unclear to what extent the long-term benefits can be distinguished from nonspecific ("placebo") effects following development of tolerance on the one hand, or prevention of related withdrawal-emergent anxiety on the other. In the past, other classes of CNS-active drugs were used for daytime sedation and to treat anxiety. Such drugs included the propanediol carbamates (notably meprobamate), and the barbiturates. Their use for anxiety is now obsolete due primarily to their tendency to cause unwanted degrees of sedation or frank intoxication at doses required to alleviate anxiety. Meprobamate and the barbiturates also can induce tolerance, physical dependence, severe withdrawal reactions, and life-threatening toxicity with overdosage. The antihistamine hydroxyzine is an effective antianxiety agent, but only at doses (about 400 mg per day) that produce marked sedation.

Propranolol and metoprolol, lipophilic p adrenergic receptor antagonists that enter the CNS, can reduce the autonomic symptoms (nervousness and muscle tremor) associated with specific situational or social phobias, but do not appear to be effective in generalized anxiety or panic disorder. Similarly, other antiadrenergic agents, including clonidine, may modify autonomic expression of anxiety, but have not been demonstrated convincingly to be clinically useful in the treatment of severe anxiety disorders.

Another class of agents with beneficial effects in disorders marked by anxiety or dysphoria of moderate intensity are the azapirones (azaspirodecanediones), A Study oftfie (BefiaviouraCanif^NeuropRarmacolbgicaf effects of some indyenous plants. 22 Cliapter-2 ^view of Citerature

currently represented clinically by buspirone (Buspar®). The azapirones have limited antidopaminergic actions in vivo and do not induce clinical extrapyramidal side effects. Also, they do not interact with binding sites for benzodiazepines or facilitate the action of GABA. They are not anticonvulsant (and may even lower seizure threshold slightly), do not appear to cause tolerance or withdrawal reactions, and do not show cross-tolerance with benzodiazepines or other sedatives. Buspirone and several experimental congeners (e.g. gepirone, ipsapirone, and tiospirone) have selective affinity for serotonin receptors of the S-HTu type, for which they appear to be partial agonist. (Lader and Scotto, 1998)

Buspirone has beneficial actions in anxious patients, particularly those with generalized anxiety of mild or moderate severity (Mendels et al., 1986; Laurence and Keith, 2008; Lader and Scotto, 1998). Unlike potent benzodiazepines and antidepressants, buspirone lacks beneficial actions in severe anxiety with panic attacks. It is not efficacious as a monotherapy in obsessive-compulsive disorder, although it may have useful anti-obsessional activity when added to SSRIs (which are efficacious as monotherapy). A lack of cross-tolerance is consistent with a lack of clinical protection against withdrawal-emergent anxiety when changing abruptly from treatment with a benzodiazepine to buspirone; a gradual transition between these classes of antianxiety agents is more likely to be tolerated (Lader and Scotto, 1998).

Major affective and anxiety disorders continue to represent the most common psychiatric illnesses, and are those most often encountered by primary-care clinicians. Major depression may well represent a spectrum of disorders, varying in severity from mild and self-limited conditions that approach everyday human distress to extraordinarily severe, psychotic, incapacitating, and deadly diseases. Rates of diagnosis and appropriate treatment of major mood disorders have improved somewhat in recent years with the advent of better-accepted and safer mood-altering medicines. Nevertheless, the majority of patients with depression or bipolar disorder are diagnosed after years of delay, if at all, and many remain inadequately treated or studied, especially children, the elderly, those with bipolar depression, and those with severe, chronic, or psychotic forms of depression.

The major limitation to developing new antidepressant and antianxiety drugs is a fundamental lack of a coherent pathophysiology and etiology for major depression, bipolar disorder, and common anxiety disorders. Current medications A Study of the (Beliaviourcd and^europfiarmacologicaC effects of some indigenous pQints. 23 Cfiapter-2

(SSRIs and tricyclic antidepressants) focus on blockade of norepinephrine and serotonin uptake, thereby prolonging their synaptic effects. The relative success of these agents creates a conceptual impasse that limits identification of novel therapeutic targets for these disorders.

2.2.4 Epilepsy:

John Jackson who is considered as father of modem concepts of epilepsy, more than 100 years ago described epilepsy as "occasional, sudden, excessive rapid and local discharges of grey matter" (Dandiya and Kulkami, 2002). The term 'epilepsies' is a collective designation for a group of CNS disorders having in common the occurrence of sudden and transitory episodes (seizures) of abnormal phenomena of motor (convulsion), sensory, autonomic or psychic origin. Such abnormal brain discharges are called seizures.

Seizures can be broadly categorized into generalized and partial (localized) types. The more common generalized seizures are:

Seizure type:

1) Generalized:

a. Tonic-clonic (Grand mal): Tonic rigidity of extremities followed by massive clonic jerking for several minutes; urinary incontinence, stupor follows onset at any age.

b. Simple absence (Petit mal): Sudden loss of consciousness upto 30 seconds can occur hundreds of times a day;

c. Myoclonic jerking: Sudden, violet contractions of extremities, with or without loss of consciousness;

d. Atonic/ Akinetic: Sudden loss of muscle tone lasting 10-60 seconds;

e. Infantile spasms (hypsarrhythmia); Brief, recurrent myoclonic jerks with abrupt flexion/ extension of limbs or whole body.

2) Partial: a. Simple seizure (focal or Jacksonian seizures): Manifestations variable depending on site of lesion; convulsions confined to a single limb muscle group; no impairment of consciousness; sensory disturbances occur;

Ji StiuCy of the (Be/iaviouraC and"T^europftarmacotbgicaf effects of some ituGgenous pCants. 24 Cfiapter-2

b. Complex partial seizures (Psychomotor epilepsy): Confused behaviour, with involuntary, purposeless, repetitive motor activity; accompanied by autonomic manifestations and loss of consciousness; seizure last several minutes, but patients have no recall of attacks.

These seizures are almost always associated with abnormal and excessive electroencephalogram (EEG) discharges. Epilepsy may be associated with an ascertained disease of the brain, and some forms of epilepsy appear to have a genetic predisposition. Thus, epilepsy is not clearly definable disease, but rather a syndrome characterized by a charge in the chemical environment of the CNS cells, which leads to an alternation in the ionic equilibrium clinically expressed as a dysfunction due to neuronal hyperexcitability.

Epilepsy is one of the oldest neurological conditions known to humankind. The term "epilepsy" is derived from Greek word "epilambanein", which means "to seize upon" or "to attack". In this modem era, epilepsy is the most fi-equent neurodegenerative disease after stroke. It afflicts more than 2 million Americans and 50 million people worldwide, and the temporal lobe epilepsy (TLE) is among the most frequent types of drug-resistant epilepsy. Epileptic seizures often cause transient impairment of consciousness, leaving the individual at risk of bodily harm and often interfering with education and employment. (Engel 1996; Engel, 2001; McNamara, 2006)

Epilepsy continues to be a neurological disorder awaiting safer drugs with improved anticonvulsant and anti-epileptogenic effectiveness as currently available drugs fail to provide adequate control of epileptic seizures in about one-third of patients and do not prevent progressive epileptogenic changes are not well understood. This fact has stimulated a considerable number of researches of new anti- epileptic drugs. In this regard, the medicinal plants have been an important source to the development of drugs with this biological activity. Additionally, numerous herbal medicines are recognized as active in the central nervous system (CNS), and they have at least a hypothetical potential to affect chronic conditions such as anxiety, depression, headaches or epilepsy that do not respond well to conventional treatments.

Novel anti epileptic drugs continue to be an elusive enigma that needs in depth research and novel vistas of anti epileptic drugs need to be explored. There are many

A Study oftfie (BeRavwuraCamfJ^euiiopfiaimacolbgicaC effects of some indigenous plants. 25 Cfiapter-2

plants which are used in the tribal and traditional Indian system of waiting for pharmacological evidence. Hence this study was designed to explore the antiepileptic activity of cassia fistula which has been used to counter epileptic seizures over centuries. The present allopathic pharmacotherapy in the management of epilepsy depends upon nature and type of epilepsy. It is reported that about 30% of patient require polytherapy for better control, which in turn increases the chance of drug-drug interaction and side effects. Unfortunately drugs used not only fail to control the seizure activity in some patients, but they frequently cause side effects. In addition safety, tolerability, efficiency, expenses especially in long term therapy, serum drug monitoring etc. are other limitation with anti epileptic drugs the review of literature clearly shows that anticonvulsant potential of various herbal medication that are now documented significantly, the report of pedicle mechanism of action shown that the identification of particular fraction and or active constituents can further provide more extensive results comparatively lesser side effect and interaction associated with this herbal remedies can make anticonvulsant treatment more rational and friendly. (Engel 1996; Engel, 2001; McNamara, 2006)

Nature and mechanisms of seizures and antiseizure drugs:

Partial epilepsies:

More than a century ago, John Hughlings Jackson, the father of modem concepts of epilepsy, proposed that seizures were caused by "occasional, sudden, excessive, rapid and local discharges of gray matter," and that a generalized convulsion resulted when normal brain tissue was invaded by the seizure activity initiated in the abnormal focus. This insightful proposal provided a valuable framework for thinking about mechanisms of partial epilepsy. The advent of the electroencephalogram (BEG) in the 1930s permitted the recording of electrical activity from the scalp of humans with epilepsy and demonstrated that the epilepsies are disorders of neuronal excitability. The pivotal role of synapses in mediating communication among neurons in the mammalian brain suggested that defective synaptic function might lead to a seizure. That is, a reduction of inhibitory synaptic activity or enhancement of excitatory synaptic activity might be expected to trigger a seizure; pharmacological studies of seizures supported this notion. The neurotransmitters mediating the bulk of synaptic transmission in the mammalian brain are amino acids, with y-aminobutyric acid (GABA) and glutamate being the principal

A Study oftfie

In most cortical neurons, the DS is generated by a large excitatory synaptic current that can be enhanced by activation of voltage-regulated intrinsic membrane currents. Although the mechanisms generating the DS are increasingly understood, it remains unclear whether the interictal spike triggers a seizure, inhibits a seizure, or is an epiphenomenon with respect to seizure occurrence in an epileptic brain. While these questions remain unanswered, study of the mechanisms of DS generation set the stage for inquiry into the cellular mechanisms of a seizure.

A Study of the (RefiaviouraC and ^europfiarmacotogicaC effects of some indigenous plants. Cfiapter-2 9jview ofCiterature

Generalized-onset epilepsies:

In contrast to partial seizures, which arise from localized regions of the cerebral cortex, generalized-onset seizures arise from the reciprocal firing of the thalamus and cerebral cortex. Among the diverse forms of generalized seizures, absence seizures have been studied most intensively. The striking synchrony in appearance of generalized seizure discharges in widespread areas of neocortex led to the idea that a structure in the thalamus and/or brainstem (the "centrencephalon") synchronized these seizure discharges. Focus on the thalamus in particular emerged from the demonstration that low-frequency stimulation of midline thalamic structures triggered EEG rhythms in the cortex similar to spike-and-wave discharges characteristic of absence seizures. (Laurence and Keith, 2008)

Intracerebral electrode recordings from humans subsequently demonstrated the presence of thalamic and neocortical involvement in the spike-and-wave discharge of absence seizures. Many of the structural and functional properties of the thalamus and neocortex that lead to the generalized spike-and-wave discharges have been elucidated. The EEG hallmark of an absence seizure is generalized spike-and-wave discharges at a frequency of 3 per second (3 Hz). These bilaterally synchronous spike- and-wave discharges, recorded locally from electrodes in both the thalamus and the neocortex, represent oscillations between the thalamus and neocortex. A comparison of EEG and intracellular recordings reveals that the EEG spikes are associated with the firing of action potentials and the following slow wave with prolonged inhibition. These reverberatory, low-frequency rhythms are made possible by a combination of factors, including reciprocal excitatory synaptic connections between the neocortex and thalamus as well as intrinsic properties of neurons in the thalamus. One intrinsic property of thalamic neurons that is pivotally involved in the generation of the 3-Hz spike-and-wave discharges is a particular form of voltage-regulated Ca^"^ current, the low threshold ("T") current. In contrast to its small size in most neurons, the T current in many neurons throughout the thalamus has large amplitude. Indeed, bursts of action potentials in thalamic neurons are mediated by activation of the T current. The T current plays an amplifying role in thalamic oscillations, with one oscillation being the 3 Hz spike-and-wave discharge of the absence seizure. Importantly, the principal mechanism by which anti-absence-seizure drugs (ethosuximide, valproic acid) are thought to act is by inhibition of the T current. Thus, inhibiting voltage-regulated ion

Ji Study of the (BeRaviouraC and TfeufopfiarmacotoQicaC effects of some indigenous plants. 28 Cfiapter-2 ^view of Citerature

channels is a common mechanism of action of antiseizure drugs, with anti-partial- seizure drugs inhibiting voltage-activated Na^ channels and anti-absence-seizure drugs inhibiting voltage-activated Ca^^ channels. (Laurence and Keith, 2008)

Therapeutic aspects:

The ideal antiseizure drug would suppress all seizures without causing any unwanted effects. Unfortunately, the drugs used currently not only fail to control seizure activity in some patients, but frequently cause unwanted effects that range in severity from minimal impairment of the CNS to death from aplastic anemia or hepatic failure. The clinician who treats patients with epilepsy is thus faced with the task of selecting the appropriate drug or combination of drugs that best controls seizures in an individual patient at an acceptable level of untoward effects. As a general rule, complete control of seizures can be achieved in up to 50% of patients, while another 25% can be improved significantly. The degree of success varies as a function of seizure type, cause, and other factors. (Laurence and Keith, 2008)

To minimize toxicity, treatment with a single drug is preferred. If seizures are not controlled with the initial agent at adequate plasma concentrations, substitution of a second drug is preferred to the concurrent administration of another agent. However, multiple-drug therapy may be required, especially when two or more types of seizure especially when two or more types of seizure occur in the same patient. Measurement of drug concentrations in plasma facilitates optimizing antiseizure medication, especially when therapy is initiated, after dosage adjustments, in the event of therapeutic failure, when toxic effects appear, or when multiple-drug therapy is instituted. However, clinical effects of some drugs do not correlate well with their concentrations in plasma, and recommended concentrations are only guidelines for therapy. The ultimate therapeutic regimen must be determined by clinical assessment of effect and toxicity. (Laurence and Keith, 2008)

2.2.5 Neurodegenerative disorders: Parkinson's disease (PD), Huntington's disease (HD), Alzheimer's disease (AD), and Amyotrophic lateral sclerosis (ALS) are characterized by progressive and irreversible loss of neurons from specific regions of the brain. The pharmacotherapy of these neurodegenerative disorders is limited mostly to symptomatic treatments that do not alter the course of the underlying disease. A striking feature of these disease

^ study of the (BefiaviovraC and ^feuropharmacolbgkaC effects of some indigenous pbtits. chapter-! ^view of Citerature

processes is their specificity for particular types of neurons. In PD there is extensive destruction of the dopaminergic neurons of the substantia nigra; neurons in the cortex and many other areas of the brain are unaffected. In contrast, neural injury in AD is most severe in the hippocampus and neocortex, and even varies dramatically in different functional corticalmregions. In HD, the mutant gene responsible for the disorder is expressed throughout the brain and in many other organs, yet the pathological changes are most prominent in the neostriatum. In ALS, there is loss of spinal motor neurons and the cortical neurons that provide their descending input. Currently, the processes of neural injury are viewed as the interaction of genetic and environmental influences with the intrinsic physiological characteristics of the affected populations of neurons. Genetic predisposition plays a role in the etiology of neurodegenerative disorders. The decline in metabolic activity with age, oxidative stress, and the local production of oxygen radicals from the metabolism of dopamine via the Fenton reaction may play roles in the etiology of some of these diseases. (Laurence and Keith, 2008)

2.2.5.1 Parkinson's disease:

Pathophysiology: Parkinsonism has four cardinal features: bradykinesia (slowness and poverty of movement), muscular rigidity, resting tremor (which usually abates during voluntary movement), and an impairment of postural balance leading to disturbances of gait and falling. The pathological hallmark of PD is a loss of the pigmented, dopaminergic neurons of the substantia nigra pars compacta (SNpc) that provide dopaminergic innervation to the striatum (caudate and putamen). Progressive loss of dopaminergic neurons is a feature of normal aging; however, symptoms of PD coincide with excessive loss (70-80%) of these neurons. Without treatment, PD progresses over 5-10 years to a rigid, akinetic state in which patients are incapable of caring for themselves. Death frequently results from complications of immobility, including aspiration pneumonia or pulmonary embolism. The availability of effective pharmacological treatment has altered radically the prognosis of PD; in most cases, good functional mobility can be maintained for many years, and the life expectancy increased substantially. Several disorders other than PD also may produce Parkinsonism, including some relatively rare neurodegenerative disorders, stroke, and intoxication with dopamine-receptor antagonists. Drugs in common clinical use that may cause parkinsonism include antipsychotics such as haloperidol and thorazine and

Ji Study oftfie (BefiavburaC and 9feuropfiarmacolbgicaC effects of some indigenous plants. 30 Cfiapter-2 ^view of Citerature

antiemetics such as prochloperazine and metoclopramide. Parkinsonism arising from other causes usually is refractory to all forms of treatment. (Laurence and Keith, 2008)

Neural mechanism of parkinsonism:

The basal ganglia can be viewed as a modulatory side loop that regulates the flow of information from the cerebral cortex to the motor neurons of the spinal cord. The net effect of stimulation of the direct pathway at the level of the striatum is to increase the excitatory outflow from the thalamus to the cortex; the net effect of stimulating the indirect pathway at the level of the striatum is to reduce the excitatory outflow from the thalamus to the cerebral cortex. The key feature of this model of basal ganglia function that accounts for the symptoms observed in PD as a result of loss of dopaminergic neurons is the differential effect of dopamine on the direct and indirect pathways. The striatal neurons of the direct pathway express primarily the excitatory Di dopamine receptor protein, whereas the striatal neurons forming the indirect pathway express primarily the inhibitory D2 type. Thus, dopamine released in the striatum tends to increase the activity of the direct pathway and reduce the activity of the indirect pathway. The net effect of the reduced dopaminergic input in PD is to increase markedly the inhibitory outflow from the SNpr and globus pallidus interna (GPi) to the thalamus and reduce excitation of the motor cortex. (Laurence and Keith, 2008)

Despite limitations, the model has utility for the rational design and use of pharmacological agents in PD. First, it suggests that to restore the balance of the system through stimulation of dopamine receptors, the complementary effect of actions at both Di and D2 receptors, as well as the possibility of adverse effects that may be mediated by D3, D4, or D5 receptors, must be considered. Second, it explains why replacement of dopamine is not the only approach to the treatment of PD. Drugs that inhibit cholinergic receptors are also effective; although their mechanisms of action are not completely understood, their effects are likely mediated at the level of the striatal projection neurons, which normally receive cholinergic input from striatal cholinergic interneurons. Few clinically useful drugs for parkinsonism are presently available based on actions through g-aminobutyric acid (GABA) and glutamate receptors. (Laurence and Keith, 2008)

A Stiufy of the (BefiaviouraC and ^KeuropharmacoCogicaC effects of some indigenous plants. Cfiapter-2 ^view of Citerature

Treatment of parkinson's disease:

a) The metabolic precursor of dopamine:

Levodopa (L-DOPA, Larodopa®, L-3, 4-dihydroxyphenylalanine), the metabolic precursor of dopamine, is the single most-effective agent in the treatment of PD; the therapeutic and adverse effects of levodopa result from its decarboxylation to dopamine. In practice, levodopa is generally administered with a peripherally acting inhibitor of aromatic L-amino acid decarboxylase (AAD) (e.g., carbidopa, benserazide) that does not penetrate well into the CNS. This increases the fraction of administered levodopa that remains unmetabolized and available to cross the blood- brain barrier and reduces the incidence of nausea and other GI side effects due to peripheral conversion of the drug to dopamine. (Laurence and Keith, 2008)

b) Dopamine-receptor agonists:

Direct agonists of striatal dopamine receptors offer several potential advantages. Since enzymatic conversion of these drugs is not required for activity, they do not depend on the functional capacities of the nigrostriatal neurons. Most dopamine-receptor agonists in clinical use have durations of action substantially longer than that of levodopa and are useful in the management of dose-related fluctuations in motor state. Finally, if fi-ee radical formation from dopamine metabolism actually contributes to neuronal death, then dopamine-receptor agonists may modify the course of the disease by reducing endogenous release of dopamine as well as the need for exogenous levodopa. Four orally administered dopamine-receptor agonists are available for treatment of PD: two older agents, bromocriptine (Parlodel®) and pergolide (Permax®); and two newer, more selective compounds, ropinirole (Requip®) and pramipexole (Mirpex®). (Laurence and Keith, 2008)

c) Catechol-o-methyitransferase inhibitors:

Catechol-o-methyltransferase (COMT) metabolizes levodopa as well as dopamine, producing the pharmacologically inactive compounds 3-O-methyl DOPA (from levodopa) and 3-methoxytyramine (from dopamine). Approximately 99% of an orally administered dose of levodopa does not reach the brain but, rather, is decarboxylated to dopamine, which causes nausea and hypotension. Addition of an AAD inhibitor (e.g., carbidopa) reduces the formation of dopamine but increases the fraction of levodopa that is methylated by COMT. COMT inhibitors will block this

Jl Study of the

peripheral conversion of levodopa to 3-0-metiiyl DOPA, increasing both the plasma ti/2 of levodopa as well as the fraction that reaches the CNS. Two COMT inhibitors are available for this use, tolcapone (Tasmar®) and entacapone (Comtan®). (Laurence and Keith, 2008)

d) Selective MAO-B inhibitors:

Two isozymes of MAO (MAO-A and MAO-B) oxidize monoamines and both are present in the periphery and GI tract; MAO-B is the predominant form in the striatum and is responsible for most of the oxidative metabolism of dopamine in the brain. At low-to-moderate doses (10 mg/day or less), selegiline (Eldepryl®) selectively and irreversibly inhibits MAO-B (Laurence and Keith, 2008)

e) Muscarinic receptor antagonists:

Antagonists of muscarinic acetylcholine (ACh) receptors were used widely for the treatment of PD before the discovery of levodopa. The biological basis for the therapeutic actions of anticholinergics is not completely understood. These drugs probably act in the neostriatum through the receptors that normally mediate the response to intrinsic cholinergic innervation of this structure, which arises primarily from cholinergic striatal intemeurons. The agents acting as muscarinic antagonists currently used in the treatment of PD include trihexyphenidyl (Artane®, 2-4 mg three times per day), benztropine mesylate (Cogentin®, 1-4 mg two times per day), and diphenhydramine hydrochloride (Benadryl®, 25-50 mg three to four times per day; diphenhydramine also is a histamine HI antagonist. All have modest antiparkinsonian activity that is useful in the treatment of early PD or as an adjunct to dopamimetic therapy. (Laurence and Keith, 2008)

2.2.5.2 Alzheimer's disease:

Pathophysiology:

AD produces an impairment of cognitive abilities that is gradual in onset but relentless in progression. Impairment of short-term memory usually is the first clinical feature; retrieval of distant memories is preserved relatively well. As the condition progresses, additional cognitive abilities are impaired, among them the ability to calculate, exercise visuospatial skills, and use common objects and tools (ideomotor apraxia). The level of arousal or alertness of the patient is not affected until the

A Study of the (BehaviouraC and ^KeumpharmacobgicaC effects of some indigenous plants. Cdapter-Z

condition is very advanced, nor is there motor weakness, although muscular contractures are an almost universal feature of advanced stages of the disease. Death, most often from a complication of immobility such as pneumonia or pulmonary embolism, usually ensues within 6-12 years of onset. The diagnosis of AD is based on careful clinical assessment of the patient and appropriate laboratory tests to exclude other disorders that may mimic AD; at present, no direct antemortem confirmatory test exists. (Laurence and Keith, 2008)

AD is characterized by marked atrophy of the cerebral cortex and loss of cortical and subcortical neurons. The pathological hallmarks of AD are senile plaques, which are spherical accumulations of the protein P-amyloid accompanied by degenerating neuronal processes, and abundant neurofibrillary tangles, composed of paired helical filaments and other proteins. In advanced AD, senile plaques and neurofibrillary tangles are most abundant in the hippocampus and associative regions of the cortex, whereas areas such as the visual and motor cortices are relatively spared. This corresponds to the clinical features of marked impairment of memory and abstract reasoning, with preservation of vision and movement. (Laurence and Keith, 2008)

Treatment of Alzheimer's disease:

The treatment of AD has involved attempts to augment the cholinergic function of the brain. Precursors of ACh synthesis, such as choline chloride and phosphatidyl choline (lecithin) do not produce clinically significant effects; however, inhibitors of acetylcholinesterase (AChE) have shown efficacy. Four inhibitors of AChE currently are approved by the FDA for treatment of AD: tacrine (1,2,3,4- tetrahydro-9-aminoacridine; Cognex®), donepezil (Aricept®), rivastigmine (Excelon®), and galantamine (Razadyne®). Tacrine is a potent centrally acting inhibitor of AChE. Oral tacrine, in combination with lecithin, produces modest effects on memory performance, and the side effects of tacrine often are significant and dose- limiting; abdominal cramping, anorexia, nausea, vomiting, and diarrhea are observed in up to one-third of patients receiving therapeutic doses, and elevations of serum transaminases are observed in up to 50% of those treated. Because of significant side effects, tacrine is not used widely clinically. (Laurence and Keith, 2008)

Jl Sttufy of the (BehaviowaCanS^mropfiarnuicoCogicd effects of some indigenous plants. 34 Cfiapter-2 ^view of Citerature

Donepezil is a selective inhibitor of AChE in the CNS with little effect on peripheral AChE. It produces modest improvements in cognitive scores in AD patients and has a long Ua, allowing once-daily dosing. Rivastigmine and galantamine are dosed twice daily and produce a similar degree of cognitive improvement. Adverse effects associated with donepezil, rivastigmine, and galantamine are similar in character but generally less frequent and less severe than those observed with tacrine: nausea, diarrhea, vomiting, and insomnia. Donepezil, rivastigmine, and galantamine are not associated with the hepatotoxicity that limits the use of tacrine. (Laurence and Keith, 2008)

An alternative strategy for the treatment of AD is the use of the NMDA glutamate-receptor antagonist memantine (Namenda®). Memantine produces a use- dependent blockade of NMDA receptors. In patients with moderate-to-severe AD, use of memantine is associated with a reduced rate of clinical deterioration. Whether this is due to a true disease-modifying effect, possibly reduced excitotoxicity, or is a symptomatic effect of the drug is unclear. Adverse effects of memantine usually are mild and reversible and may include headache or dizziness. (Laurence and Keith, 2008)

2.2.5.3 Huntington's disease (HD):

Pathophysiology of HD:

HD is a dominantly inherited disorder characterized by the gradual onset of motor incoordination and cognitive decline in midlife. Symptoms develop insidiously, either as a movement disorder manifest by brief, jerk-like movements of the extremities, trunk, face, and neck (chorea) or as personality changes or both. Fine motor incoordination and impairment of rapid-eye-movements are early features. Occasionally, choreic movements are less prominent and bradykinesia and dystonia predominate. As the disorder progresses, the involuntary movements become more severe, dysarthria and dysphagia develop, and balance is impaired. The cognitive disorder manifests first as slowness of mental processing and difficulty in organizing complex tasks. Memory is affected, but affected persons rarely lose their memory of family, friends, and the immediate situation. Such persons often become irritable, anxious, and depressed. Less frequently, paranoia and delusional states are manifest. The outcome of HD is invariably fatal; over a course of 15-30 years, the affected

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person becomes totally disabled and unable to communicate, requiring full-time care; death ensues from the complications of immobility. (Laurence and Keith, 2008)

HD is characterized by prominent neuronal loss in the striatum (caudate/putamen). Atrophy of these structures proceeds in an orderly fashion, first affecting the tail of the caudate nucleus and then proceeding anteriorly from mediodorsal to ventrolateral. Other areas of the brain also are affected, although much less severely; one result is a prominent decrease in striatal GABA concentrations, whereas somatostatin and dopamine concentrations are relatively preserved. In most adult-onset cases, the medium spiny neurons that project to the GPi and SNpr (the indirect pathway) appear to be affected earlier than those projecting to the GPe (the direct pathway). The disproportionate impairment of the indirect pathway increases excitatory drive to the neocortex, producing involuntary choreiform movements. In some individuals, rigidity rather than chorea is the predominant clinical feature; this is especially common in juvenile-onset cases. In these cases, the striatal neurons giving rise to both the direct and indirect pathways are impaired to a comparable degree. (Laurence and Keith, 2008)

Treatment of Huntington's disease:

No current treatment slows the progression of HD, and many medications can impair function because of side effects. Treatment is needed for patients who are depressed, irritable, paranoid, excessively anxious, or psychotic. Depression can be treated effectively with standard antidepressant drugs with the caveat that drugs with substantial anticholinergic profiles can exacerbate chorea. Fluoxetine is effective treatment for both the depression and the irritability manifest in symptomatic HD; carbamazepine also is effective for depression. Paranoia, delusional states, and psychosis usually require treatment with antipsychotic drugs, but the doses required often are lower than those usually used in primary psychiatric disorders. These agents also reduce cognitive function and impair mobility and thus should be used in the lowest doses possible and should be discontinued when the psychiatric symptoms resolve. (Laurence and Keith, 2008)

In individuals with predominantly rigid HD, clozapine, quetiapine, or carbamazepine may be more effective for treatment of paranoia and psychosis. The movement disorder of HD per se only rarely justifies pharmacological therapy. For

Ji Study of the (BefiaviouraC andO^europharntacotogicaC effects of some indigenous plants. 36 Chapter-2 ^view of literature

those with large-amplitude chorea causing frequent falls and injury, dopamine- depleting agents such as tetrabenazine and reserpine can be tried, although patients must be monitored for hypotension and depression. Antipsychotic agents also can be used, but these often do not improve overall function because they decrease fine motor coordination and increase rigidity. Many HD patients exhibits worsening of involuntary movements as a result of anxiety or stress. In these situations, judicious use of sedative or anxiolytic benzodiazepines can be very helpful. In juvenile-onset cases, where rigidity rather than chorea predominates, dopamine agonists variably improve rigidity. These individuals also occasionally develop myoclonus and seizures that can be responsive to clonazepam, valproic acid, and other anticonvulsants. (Laurence and Keith, 2008)

HD is characterized by loss of neurons from the striatum. The neurons that project from the striatum to the GPe and form the indirect pathway are affected earlier in the course of the disease than those which project to the GPi. This leads to a loss of inhibition of the GPe. The increased activity in this structure, in turn, inhibits the STN, SNpr, and GPi, resulting in a loss of inhibition to the VAA^L thalamus and increased thalamocortical excitatory drive. Structures in light blue have reduced activity in HD, whereas structures in dark blue have increased activity. (Laurence and Keith, 2008)

2.2.6 Psychiatric disorders:

The psychotic disorders include schizophrenia, the manic phase of bipolar (manic-depressive) illness, acute idiopathic psychotic illnesses, and other conditions marked by severe agitation. All exhibit major disturbances in reasoning, often with delusions and hallucinations. The psychoses are among the most severe psychiatric disorders, in which there is not only marked impairment of behavior but also a serious inability to think coherently, to comprehend reality, or to gain insight into the presence of these abnormalities. These common disorders (affecting perhaps 1% of the population at some age) typically include symptoms of false beliefs (delusions) and abnormal sensations (hallucinations). (Laurence and Keith, 2008)

Representative syndromes in this category include schizophrenia, brief psychoses, and delusional disorders. Psychotic features also occur in major mood disorders, particularly mania and severe melancholic depression. Psychotic illnesses

A Study of the (BehaviouraC and TfeuropfiarmacoCogicaC effects of some indigenous pCants. 37 Cfiapter-2 ^view of Citerature

are characterized by disordered thought processes (as inferred from illogical or highly idiosyncratic communications) with disorganized or irrational behavior and varying degrees of altered mood that can range from excited agitation to severe emotional withdrawal. Idiopathic psychoses characterized by chronically disordered thinking and emotional withdrawal, and often associated with delusions and auditory hallucinations, are called schizophrenia. Acute and recurrent idiopathic psychoses that bear an uncertain relationship to schizophrenia or the major affective disorders also occur. Delusions that are more or less isolated are characteristic of delusional disorder or paranoia. (Laurence and Keith, 2008)

Several classes of drugs are effective for symptomatic treatment. Antipsychotic agents also are useful alternatives to electroconvulsive therapy (ECT) in severe depression with psychotic features, and sometimes are used in the management of patients with psychotic disorders associated with delirium or dementia or induced by other agents (e.g., stimulants or L-DOPA). The term neuroleptic is often applied to drugs that have relatively prominent experimental and clinical evidence of antagonism of D2 dopamine (DA) receptors, with substantial risk of adverse extrapyramidal neurological effects and increased release of prolactin. The term atypical antipsychotic is applied to agents that are associated with substantially lower risks of such extrapyramidal effects. Although the antipsychotic drugs have had a revolutionary, beneficial impact on medical and psychiatric practice, their liabilities, especially of the older typical or neuroleptic agents, must be emphasized. Newer antipsychotics are atypical in having less risk of extrapyramidal side effects, but these agents present their own spectrum of adverse effects, including hypotension, seizures, weight gain, and increased risk of type 2 diabetes mellitus and hyperlipidemia. (Laurence and Keith, 2008)

The beneficial effects of antipsychotic drugs are not limited to schizophrenia. They also are employed in disorders ranging from postsurgical delirium and amphetamine intoxication to paranoia, mania, psychotic depression, and the agitation of Alzheimer's dementia (although their efficacy in this disorder in not proven). They are especially useful in severe depression and possibly in other conditions marked by severe turmoil or agitation. (Laurence and Keith, 2008)

Antipsychotic drugs share many pharmacological effects and therapeutic applications. Chlorpromazine and haloperidol are prototypic of the older, standard A Study of the (BefiaviouTaC and T^europhamacobgicaC effects of some iiufigenous plants. 38 Cfiapter-2 ^view of Citerature

neuroleptic-type agents. Many antipsychotic drugs, especially chlorpromazine and other agents of low potency, have a prominent sedative effect. This is particularly conspicuous early in treatment, although some tolerance typically develops and can be of added value when very agitated psychotic patients are treated. Despite their sedative effects, neuroleptic drugs generally are not used to treat anxiety disorders or insomnia, largely because of their adverse autonomic and neurologic effects, which paradoxically can include severe anxiety and restlessness (akathisia). The risk of developing adverse extrapyramidal effects, including tardive dyskinesia, following long-term administration of neuroleptic drugs makes them less desirable than several alternative treatments for anxiety disorders (Laurence and Keith, 2008)

The term neuroleptic was intended to contrast the effects of drugs such as chlorpromazine to those of sedatives and other CNS depressants. The neuroleptic syndrome involves suppression of spontaneous movements and complex behaviors, whereas spinal reflexes and unconditioned nociceptive-avoidance behaviors remain intact. In humans, neuroleptic drugs reduce initiative and interest in the environment as well as manifestations of emotion. In clinical use, there may be some initial drowsiness and slowness in response to external stimuli. However, subjects are easily aroused, can answer questions, and retain intact cognition. Ataxia, incoordination, or dysarthria do not occur at ordinary doses. Typically, psychotic patients soon become less agitated, withdrawn or autistic patients sometimes become more responsive and communicative, and aggressive and impulsive behavior diminishes. Gradually (usually over days), psychotic symptoms of hallucinations, delusions, and disorganized or incoherent thinking ameliorate. Neuroleptic agents also exert characteristic neurological effects—including bradykinesia, mild rigidity, tremor, and akathisia—that resemble the signs of Parkinson's disease. Although the term neuroleptic initially encompassed this whole unique syndrome and is still used as a synonym for antipsychotic, it now is used to emphasize the more neurological aspects of the syndrome {i.e., the parkinsonian and other extrapyramidal effects). Except for clozapine, aripiprazole, quetiapine, ziprasidone, and low doses of olanzapine and risperidone, antipsychotic drugs available in the U.S. also have effects on movement and posture and can be called neuroleptic. The more general term antipsychotic is preferable, as reinforced by the growing number of modem atypical antipsychotic drugs with little extrapyramidal action. (Laurence and Keith, 2008)

A Study qft/ie (BefiavwuraC and !Nimropfiarnuicol6gicaC effects of some indigenous plants. 39 Cfiapter-2 (Review of Citerature

A number of effects in animal behavioral models have been used to predict the efficacy or potential adverse effects of antipsychotic agents. Despite their widespread use, these paradigms generally have not provided important insights into the basis for clinical antipsychotic effects. (Laurence and Keith, 2008)

The acute adverse clinical effects of antipsychotic agents are best mimicked in animals by assessing catalepsy in rats (immobility that allows an animal to be placed in abnormal postures that persist) or dystonia in monkeys. Late dyskinetic effects of antipsychotics are represented by the development of vacuous chewing movements in rats. A particularly disturbing adverse effect of most antipsychotics is restless activity, termed akathisia, which is not readily mimicked by animal behavior. The cataleptic immobility of animals treated with classical antipsychotics resembles the catatonia seen in some psychotic patients and in a variety of metabolic and neurological disorders affecting the CNS. In patients, catatonic signs, along with other features of psychotic illnesses, are sometimes relieved by antipsychotic agents. However, rigidity and bradykinesia, which mimic catatonia, can be induced by administering large doses of potent traditional neuroleptics and by addition of an anti-muscarinic anti- Parkinson agent. (Laurence and Keith, 2008) ^"ru H ci ci Cj

Several cognitive functions, including auditory processing and attention, spatial organization, verbal learning, semantic and verbal memory, and executive functions, are impaired in schizophrenia patients. Potent D2-antagonist neuroleptics have very limited beneficial effects on such functions. Some atypical antipsychotic agents with mixed D2/5-HT2A activity (including clozapine, quetiapine, olanzapine, and risperidone), as well as the D2 partial agonist aripiprazole, seem to improve cognitive functioning in psychotic patients. Nevertheless, significant long-term gains in social and occupational function during long-term treatment of chronically psychotic patients with these drugs are not well documented. (Laurence and Keith, 2008)

Antipsychotic drugs have inconsistent effects on sleep patterns but tend to normalize sleep disturbances characteristic of many psychoses and mania. The capacity to prolong and enhance the effect of opioid and hypnotic drugs appears to parallel the sedative, rather than the neuroleptic, potency of a particular agent; thus, potent, less-sedating antipsychotics do not enhance sleep. (Laurence and Keith, 2008)

^ Study of the (BeHaviouraC and !Neuropfiamuico{6gicaC effects of some indigenous plants. 40 Cfiapter-2 ^view of Citerature

The antipsychotic drugs affect all levels of the CNS. Theories on the actions of antipsychotic agents are based on their ability to antagonize the actions of DA as a neurotransmitter in the basal ganglia and limbic portions of the forebrain. Although supported by a large body of data, these theories reflect a degree (Laurence and Keith, 2008)

2.3 Various neurotransmitters involved in central nervous system:

2.3.1 Acetylcholine:

In nootropic activity:

It is generally held that acetylcholine neurotransmitter system is involved in the learning and memory. Impairment of learning and memory has frequently been reported following injection of anticholinergic agents such as atropine and scopolamine. Atropine injection has been shown to disrupt short-term memory in man and many kinds of learning tasks are impaired by injection of anticholinergic agent in experimental animals. Injection of these drugs produces consistant deficit in spontaneous alterations, extinction, successive discrimination, maze learning, acquisition and retention of passive avoidance and acquisition of some responses.

A major neurochemical change in Alzheimer's type senile dementia involves deterioration of muscarinic and nicotinic presynaptic indices in the cerebral cortex and hippocampus. Acetylcholine not only necessary for learning and memory, but its presence within the neocortex is also sufficient to ameliorate learning deficits and restore memory following damage to the nucleus basalis. Acetylcholine plays an important role in consolidation of passive avoidance. Nicotine potentiates the nicotinic cholinergic neuronal system and may potentiate acquisition of memory.

In convulsions:

Although interference within the ACh system can lead to convulsions, there is little support available in view that Ach is critically involved in the aetiology of epilepsy and in action of more than a few content of brain have been demonstrated during convulsion by a variety of agents, but these changes are almost certainly the consequences, rather than the cause of convulsions. When human cerebral cortex containing as epileptic focus was incubated in vitro, its ability to produce 'bound' ACh was much less than that of normal cortex, although the synthesis of free 'ACh'

A Study of the (BeliaviouraCaTuf^^europfiarmacoli^icaC effects of some indigenous pbnts. 41 Cfuipter-2 ^view of Citerature

was impaired. Unfortunately later study completely failed to confirm the above observation. All these experiments have sought to establish the role played by Ach in initiation of convulsions, have lead to the convulsion that, although it may be necessary for the maintenance of convulsive activity, Ach has no part to play in initiation of seizure and disturbance in metabolism cannot be the cause of convulsion.

The chronic administration phenytoin and trimethadione has been demonstrated to cause decrease in ACH content of brain, but the significance of the observation is difficult to assess as other antiepileptic agents have little or no effect on the brains Ach. Also anticholinergic drug do not posses anticonvulsant activity v^^ith which support the concept that increase in Ach level is a consequence and not reason for initiating convulsions (Engel 1996; McNamara, 2006).

In cardiovascular system:

These include cardiac slowing and a decrease in cardiac output. The latter action results mainly from a decreased force of contraction of the atria, since the ventricles have only a spare parasympathetic innervation and low sensitivity to muscarine agonist. Generalized vasodilatation also occurs and these two effects combine to produce a sharp fall in arterial pressure (Rang et al., 2003).

2.3.2 Norepinephrine:

In nootropic activity:

Most central nor-ademergic neurons are located in the nucleus locus coeruleus of the pons and in neurons of the reticular formation. Fibers from these nuclei innervate a large number of cortical, subcortical and spinomedullary fields. Many functions have been ascribed to the central nor-ademergic neurons including a role in affective disorders, in learning and memory, and in sleep wake cycle regulation. Ademergic nuclei in the locus coeruleus play amajor role in information processing. It has been shown that noradrenergic neurotransmitter system play an important role in clonidine induced disturbances of cognition, as well as in the protective effects of nootropic drugs. Piracetam, a prototype nootropic drug produces a dose- related effect on rat brain. In human subjects, emotionally influenced memory was found to block by beta- ademergic blockers. Desimipramine, a NA uptake inhibitor showed a tendency to enhance latent leaming in mice at the intermediate dose (Bhattacharya et al., 1993).

A Study oftfie (BefuxnouraC andO^mropfiartnacolbgicaC effects of some inefigenous plants. 42 Cfiapter-2 ^view ofCiterature 4= In depression:

Norepinephrine containing neurons are involved in many of the functions that are profoundly distributed in mood disorders. Alpha-adrenergic receptors are localized not only on the terminals and dendrites of noradrenergic neurons (autoreceptor) but also presynaptically as inhibitory receptors on non-noradrenergic neurons (heteroreceptors) (Anden, 1982). The ability of alpha2 autoreceptors to control the activity of ascending noradrenergic pathways underlies their role in the regulation of mood and to the pathways of psychiatric disorders such as anxiety and depression. The involvement of amygadaloid catecholaminergic mechanism in suppressive effects of deipramine and imipramine has been reported (Araki, 1985).

In convulsion:

Catecholamines (NE) are widely distributed in brain. Various workers made suggestion of NE having some role of convulsions processes. The lowering of either catesholamines or serotonin by reserpine, tertabenzine and a- methyl dopa was favorable to the production of convulsion, which was corrected by dopa, which would raise the levels of catecholamines only but not by 5-HTP, which would raise the levels of serotonin only (Bapat et al., 1973).

2.3.3 Dopamine:

In nootropic:

A large number of experiments have presented evidences suggesting that learning and memory can be modified by stimulation of central dopaminergic system in laboratory animals; however a consistent effect has been difficult to detect. Sulpiride, a dopaminergic antagonist counteracted the disruptive effect of apomorphine on latent learning. Niogrostrital dopaminergic system found to have no role in formation of the memory engram (Bhattacharya et al., 1993). However studies involvement of mesolimbacortical dopaminergic system in cognitive effects.

In depression:

Different role of dopamine Di and D 2 receptors in the depression was reported by (Nikulina, 1991). However the involvement of dopamine D2but not Dj receptors in depression have reported. (Borsini et al., 1989)

Jl Study of the (Be/iaviotirafattcfO^eurvpfiarmacolbgicaC effects of some ind^enous plants. 43 Cluipter-2

2.3.4 Serotonin:

In nootropic:

Pharmacological studies have indicated the role of serotonin (5-HT) in learning and memory. It is reported that stimulation of serotonergic neurotransmitter system impairs learning and memory function. Increased serotonin in brain may decrease the release of acetylcholine via 5-HT receptor activation, recent investigation shows that selective damage to 5-HT system is not sufficient to impair memory, but that combined damage to the serotenergic and nor-ademergic system can disrupt a performance task that requires recent memory. Alzheimer's disease involves impairment of ACh, 5-HT and NA system. Serotonin antagonist and depletion of brain 5-HT have been reported to facilitate learning and enhance retentionprocess in avoidance tasks. The treatment with FK 960. [N-(4-acetyl-l-piperazomyl)-p- flurobenzamide monohydrate], memory enhancer, showed dose dependent increase in serotonin content. The beneficial effect of p-hydroxybenzyl alcohol on cyclohexamide-induced impairment was found to be amplified but reduced by serotonergic 5-HT2A and 5-HT2 receptor antagonists.

In depression:

The classical mechanism of antidepressant is by increasing by effective synaptic concentration of monoamines, nor-epinephrine, 5-HT and dopamine either by blocking the oxidative enzyme in synaptic terminals that degrade these monoamines (e.g. MAO inhibitors) or by blocking the reuptake of these neurotransmitters, i.e. reuptake blockers. It has been shown that many antidepressant antagonists at 5 -HTic receptors in the brain (Jenck, et al., 1993). Several antidepressant drugs exhibited affinity for (^H) quipazine labeled 5-HT3 binding sites but not to (^H) zacopride and (^H) tropisetron 5-HT3 binding sites. These finding have led to interest in the potential aspect of 5-HT3 receptor involvements.

In convulsion:

It has been reported that several anticonvulsant drugs as bromides, phenytion, phenurone, primidone and trimethdione increase 5-HT content of brain. A considerable profit might occur from a more detailed investigation into relationship between 5-HT and epileptic activity. Depletion of brain serotonin level by treatment with serotonin synthesis inhibitors, p-chloro-phenylalanine increased the percentage

A Study of the ^efiavhuraCamf!NeuropliarmacoQ>gicaC effects of some indigenous plants, 44 Cfiapter-2 ^view ofCiterature I # of mice exhibiting electrically induced seizures, which were prevented by administration of serotonin precursor: 5-Hydroxytryptophan. GAB A or agents increasing endogenous level of GABA had synergistic effect in inhibiting the convulsion. Thus GABA-ergic and serotonergic systems are interrelated in brain at least with regard to electrically induced convulsions. (McNamara, 2006) 2.3.5 Amino acids:

A) Gamma aminobutaric acid:

In nootropic: Gamma aminobutaric acid and glycine are important inhibitory neurotransmitters. Both cause IPSPs by opening CI" channels. GABA is found only in the CNS, where it is the most common inhibitory neurotransmitter. As many as one -third of all brain synapse use GABA. Antianxiety drugs such as diazepam (Valium) enhance the action of GABA. In the spinal cord, about half of the inhibitory synapses use the amino acid glycine and half use GABA.

There is some preliminary evidence that drug which inhibit GABA receptor improve memory. Several reports have been demonstrated interaction between cholinergic and GABA/ benzodiazepine receptor system in learning and memory. Benzodiazepine antagonist showed enhancement of learning and memory in mice. Biochemical experiments suggest that there is improvement in impairment in impaired memory by facilitating cholinergic and GABAergic transmission in brain. It was suggested that nefiracetam improves the dysfunction of cholinergic, GABAergic and/ or monominergic neural functions acting at Ca^ channel and enhancing the release of neurotransmitter. The tone of GABAergic system found to increase with age, particularly in Alzheimer's disease. (Itoh et al., 1991; Hiramatasu et al., 1992; Nakagawa et al., 1996)

In depression :

GABAergic agents particularly GABAB receptors, play an important role in the modulation of action antidepressant drugs. Involvement of GABAB receptor, but not GABAA receptor system in the action of antidepressant is supported by (Nakagawa, 1996)

A Study oftfie (BeRavioiirc^ andO^europharmacologiaU effects of some imSgenous plants. 45 Cfiapter-2 ^view of Citerature

In convulsion:

The concentration of GABA in focal epileptic tissue in human subjects is lower than in the surrounding normal tissue. It has wide and relatively even distributing in brain; its concentration is about 200|ig/g in cortical tissue and about 550^g/g in mid brain.

Although marked improvement in the treatment has been made, the incidence of uncontrolled epilepsy remains high. Since GABA hypo function is thought to be one of the major aetiological factors in epilepsy, during the last two decades, most of the alteration has been focused on the developmental of GABA ergic anticonvulsant. The discovery and clinical usefulness of sodium valproate gave the necessary impetus. GABA mimetics and anti glutamate agents may there fore provide a potent anticonvulsant agent.

B) Glutamate and aspartate:

These are found in high concentration in brain to the extent of approximately 1400 to 1800 \ig/g in brain tissue. Their concentration in brain white matter is about two third of gray matter and they have excitatory function throughout the CNS.

Glutamate receptors, like those for GABA, are classified functionally either as ligand gated ion channel ("inotropic" receptor) or as "metabotropic" (G protein- coupled) receptors. Neither the precise number of subunits that assemble to generate a functional glutamate receptor ion channel in vivo nor the topography of each subunit has been established unequivocally (Rang et al., 2003).

The ligand gated ion channels are further classified according to the identity of agonist that selectively are activate each receptor subtype. These receptors include a- amino -3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), Kaniate and N- methyl-D-asparate (NMDA) receptors. (Rang et al., 2003).

NMDA receptors are assemble from two types of subunit, NRl and NR2, each of which can exist in different isoforms and splice variants, giving rise to many receptor isoforms in the brain significance of which is yet not understood. The subunits constituting AMPA and Kainate receptors are termed as Glu \.^ and KAi_2 are closely related but distinct from NR subunits. AMPA receptors consist of combination of GIUM. AMPA receptors lackin the Glu2 subunit have much higher permeability to

^ Study oftfie

Ca^^ than the others. The metabotropic receptors are monoamine G protein coupled receptor, linked to intracellular second messanger system. LTP is the term used to describe a long lasting (hours in vitro, days or weeks in vivo) enhancement of synaptic transmission that occurs at various CNS synapses following a short (conditioning) burst of presynaptic stimulation, typically at about lOOHz for 1 second. These phenomena have been studied in great details in the hippocampus, which play a central role in learning and memory. It has been argued that 'learning' in the synaptic sense, can occur if synaptic strength is enhanced following simultaneous activity in both pre and post synaptic neurons. LTP shows this characteristics; it does not occur if presynaptic activity fails to excite the postsynaptic neuron, or if the latter is activated independently, for instance by different presynaptic input. Thus LTP initiation involves enhance activation of AMPA-receptors at EAA synapses. The facilitatory process also appears to involve both pre and postsynaptic elements; the release of glutamate in increased, and so is the response of postsynaptic AMPA- receptors to glutamate. Increased expression and trafficking of AMPA-receptors to synaptic sites also occurs. (McNamara, 2006; Rang et al., 2003)

Interestingly, NMDA receptors also can induce long term depression (LTD) at CNS synapse (Malenka et al., 1999). It seems that the frequency and pattern of synaptic stimulation undergoes LTP or LTD.

NMDA receptors may also involve in the development of susceptibility to epileptic seizures and in the occurrence of seizure activity. Cases of Rasmussen's encephlities, a childhood disease leading to intractable seizures and dementia, were found to correlate with levels of serum antibodies to glutamate subunit. An increase in glutamatergic neurotransmission following blockade of (excitatory) 5-HTe receptors is surprising given that an increase in seizure threshold has been reported, but can theoretically be explained by the apparent presence of S-HTe receptors on GAB A ergic intemeurons. (McNamara, 2006; Rang et al., 2003)

In depression: Antagonists of NMDA receptor have been demonstrated to have neuroprotective, anticonvulsant, anxiolytic and muscle relaxant action. This agent inhibits the uptake of monoamines, like many established antidepressants. Since glutamatergic afferent's innervating both monoaminergic cell bodies and terminal

A Study of the (BefiaviouraC and 9/europfiamacolbgicaC effects of some indigenous plants. Cfiapter-2 ^view of Citerature $ I fields, the activity of monoaminergic system may be regulated by glutamatergic agents.

The general principles of the drug therapy of the epilepsies are summarized below:

- This effect is mediated by a slowing of the rate of recovery of voltage-activated Na"^ channels from inactivation

- Potentiation of synaptic inhibition through an action on the GABAA receptor.

- reduces low threshold Ca^"^ currents

- Inhibits synaptic release of glutamate by acting at Na"^ channels themselves.

Inhibits the GAB A transporter, GAT-1, and thereby reduces GAB A uptake into neurons and glia.

A Study of the ^efiaviourd and O^europftamacoCogicaC effects of some indigenous ptanU. 48 Cfiapter-2 ^view ofCiterature

2.4 The organization of screening: The screening of drugs involves scanning and evaluation. The scanning always involves a test or a group of tests, which, it is believed, will permit the detection of physiological activity. Unless evaluation, through another test, so that the uncertainty of the scanning is removed.

Blind screening the technique for detecting pharmacological "history," requires considerable planning and skilful execution of the tests, in order to be economical of time and money. The strategy of few tests, having simple procedures, is to be applied to cheap animals.

There are three kinds of screening for pharmaceuticals, the distinction lying in the different aims of the screening.

A) Simple Screening: When one or two tests are used to find substances having particularly property, the screening is simple; there is no need for a battery of tests in which the interpretation of results of results of one test may depend on those of another test.

B) Blind Screening: If a new series of chemical substances becomes available, either through isolation from a natural source or through synthesis, there may be no information on its pharmacological activity. Then blind screening sought to provide clues to show pharmacological inertness if it exists. The chief purposes of the screening are to demonstrate whether the new group of substances is worthy of further attention, and to indicate which among them have the most interesting pharmacological properties. Blind screening, the technique for detecting pharmacological activity in a group of substances without pharmacological 'history', requires considerable planning and skill fiill execution of the tests, in order to be economical of time and money.

C) Programmed Screening: when a new drug of specific type is sought, or when a series of compound is to be investigated for some pharmacological effects (for example, effects on the heart), a program of testing is required is provided information on the compounds that only a battery of tests can provide. The aim of the screening is more limited than for blind screening, and greater precision in the results is often expected.

A study oftfU (BehaviouraC and TTmropfiamacobgicaC effects of some indigenous pldnU. Cfiapter-2 ^view of Citerature # I Blind screening - one of the three kinds of screening - requires the most discussion. The best approach is one where no assumptions are made about what the probable actions of a compound may be, expect when an already carefully studied series of compounds having similar structures has been investigated. In drug evaluation it is important to note the whole range of qualitative changes produced by a drug and quantitative relation between them.

There are three kinds of screening for pharmaceuticals, the distinction lying in the different aims of the screening (Turner, 1965).

Ji Study of the ^efkviouraC and !NeunpfiarmacolbgicaC effects of some ind^enous plants. SO Cfiapter-2 ^view of Citerature I I 2.5 Different experimental paradigms for the evaluation of drugs for Behavioral and neuropharmacological disorders: (Vogei and Vogel, 1997)

I. Anti-aggressive activity:

1. Foot-shock induced aggression

2. Isolation-induced aggression

3. Resident-intruder aggression test

4. Water competition test

II. Tests for anxiolytic activity:

1. Anti-anxiety test (light-dark model)

2. Social interaction in rats

3. Anticipatory anxiety in mice

4. Elevated plus maze test

5. Water maze test

6. Staircase test

7. Footshock induced

8. Freezing behavior in rats

9. Experimental anxiety in mice

III. Antiepileptic activity:

1. Electroshock in mice

2. Pentylenetetrazol (Metrazol) induced convulsions

3. Strychnine-induced convulsions

4. Picrotoxin-induced convulsions

5. Isoniazid-induced convulsions

6. Yohimbine-induced convulsions

7. Kindled rat seizure model

8. Genetic animal models of epilepsy

Jl Study of the (BehaviouraC andTfmropfiarmacoCogicaC effects of some iiuRgenous plants. 51 Cfiapter-2 ^view of Citerature

IV. Hypnotic activity:

1. Potentiation of hexobarbital sleeping time

2. Experimental insomnia in rats

3. EEG registration in conscious cats

4. Automated rat sleep analysis system

V. Neuroleptic activity:

1. Golden hamster test

2. Catalepsy in rodents

3. Pole climb avoidance in rats

4. Foot -shock induced aggression

5. Amphetam ine group toxic ity

6. Inhibition of amphetamine stereotypy in rats

7. Yawning/penile

8. erection syndrome in rats

9. Inhibition of mouse jumping

VI. Antidepressant activity:

1. Catalepsy antagonism in chicken

2. Despair swim test

3. Tail suspension test in mice

4. Learned helplessness in rats

5. Muricide behavior in rats

6. Potentiation of norepinephrine toxicity

7. Compulsive gnawing in mice 8. Apomorphine-induced hypothermia in mice

9. Reserpine induced hypothermia

10. 5-Hydroxytryptophan potentiation in mice

JL Study of the (Behavhurd and ^europRamacobgicaC effects of some indigenous ptanU. Cfiapter-2 ^view of Citerature 9 » VII. Anti-Parkinsonism activity:

1. Tremorine and oxotremorine antagonism

2. MPTP model in monkeys

3. Reserpine antagonism

4. Circling behavior in nigrostriatal lesioned rats

5. Elevated body swing test

6. Skilled paw reaching in rats

7. Stepping test in rats

VIII. Learning and memory processes:

1. Inhibitory (passive) avoidance

2. Step-down

3. Step-through

4. Two compartment test

5. Up-hill avoidance

6. Scopolamine-induced amnesia in mice

7. Active avoidance

8. Runway avoidance

9. Shuttle box avoidance (two-way shuttle box)

10. Jumping avoidance (one-way shuttle box)

11. Discrimination learning

12. Spatial learning in the radial arm maze

13. Visual discrimination

14. Spatial learning in the water maze

A Study of the (BehaviouraC and 9{europliamaco(bgicaC effects of some indigenous pbnts. S3 Cfiapter-2 ^view of Citerature

2.6 Hemidesmus indicus (H. indicus):

2.6.1 Family: Asclepiadaceae

2.6.2 Synonyms and regional names:

Sanskrit - Anantmula, sariva or saribha, naga-jihva, gopa-kanya, sugsndhi,

gopimulam

Bengaoli - Anantamul

Punjabi - Anantamul

Gujarati - Sariva, upalasari, durivel

Hindi - Anantmul, Magrabu, salsa, kalisar, hindi salsa

Kanada - Karibandha, sogade

M alyalum - Naruninti

Marathi - Anantmul, upalasari, upersari, dudhasali

Oria - Onontomulo

Tamil - Nannari, kizhanna

Telgu - Sugandhi-pala, gadisugandhi, muttavapulagamu

English - Indian sarasaparilla. Country sarasaparilla

French - Periploca des Indes, Reoine de Sarlsepareille

German - Hemidesmus wurzel, sarsaparillwurzel

Arebian - Zaiyana, Ausaba lunnara

Potugis - Upercao

2.6.3 Parts used: Roots, root-bark, leaves, steam.

2.6.4 Pharmacognostical studies: 2.6.4.1 Distribution: H. indicus is a widely distributed medicinal plant in India. (Austin, 2008)

A Study of the (BehaiHouraC and^mrophamacotogicaC effects of some indigenous plants. Cfiapter-2 ^view of Citerature

2.6.4.2 Macroscopical characters:

It is a slender laticiferous, twining, sometimes prostrate or semi erect shrub, occurring over the greater part of India, from the upper gangetic plain eastwards to Assam and throughout central, western and southern India. (Anonymous, 2001)

Figure 2.3: Hemidesmus indicus (Austin, 2008)

1. Root:

Roots are woody and aromatic; stems are numerous, slender, terete, thickened at the nodes; leaves are opposite, short-petioled, very variable, elliptic-oblong to linear-lanceolate (1-4 in. X 0.3-1.5 in.), often variegated with white above, sometimes silvery white and pubescent beneath. Roots are cylindrical, 0.2-0.7 in. or more in thickness, somewhat tortuous, seldom branched, brownish or purplish in color, with a short fracture at the periphery and fibrous at the centre. The surface of the young roots is generally smooth but in older root the surface is transversely cracked and longitudinally fissured. The bark has no characteristic test or odour and is easily separable from the inner tissue surrounding the central wood, which is officinal part. In the fresh condition the inner cortical tissue is merely white in colour, but on exposure it becomes dark brown, it has characteristic fi^grance and aromatic sweetish test. (Anonymous, 2001)

IP specifications:

The drug as specified in IP should contain not more than 2% foreign organic matter and 4% ash. It should contain alcohol soluble extractives not less than 15% and water soluble extractives not less than 13.5%. The drug deteriorates with age and fresh roots are preferred. (Anonymous, 2001)

A Study of the

3. Flowers:

Pedicels are short clothed with numerous ovate acute imbricating bracts. Calyx is 205 mm long, glabrous outside, lobes 1.5 mm long, ovate, acute with membranous ciliolate margins. Corolla are 5 - 6 mm long greenish outside, purple inside, tube very short, lobes valvate, fleshy, 4 mm long, ovate oblong, acuminate. Follicles are 10 - 15 cm X 6 mm, cylindric, tapering to a point at the apex, straight or some times slightly curved, striate, glabrous. (Kirtikar and Basu, 2003)

Flowers are greenish outside, purplish inside, crowded in subsessile opposite axillary cymes; follicles are slender, 4 inches long, cylindrical, sometimes curved, divaricate. (Anonymous, 2001)

4. Seeds:

Seeds are numerous, 6-8 mm long ovate-oblong, and flattened, black, with a silvery white coma, 2.5 cm long. (Anonymous, 2001; Kirtikar and Basu, 2003)

This is a common medicinal plant widely used in Indian systems of medicine (Anonymous, 1997) and also an official drug in Indian Pharmacopoeia (Anonymous, 1996) and British Pharmacopoeia (Anonymous, 2003).

The highest concentration of glycosides, flavonoids, tannins and sterols in the entire plant during summer was reported (Austin, 2008).

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2.6.4.3 Phytochemical studies: (Austin, 2008)

1. Root: Air dried roots were yield 0.225% essential oil (sp. gr. 0.9553; 1.5342) containing p-methoxy salicylic aldehyde (m. p. 42°C) as the major constituent (80%). Other constituent present in the roots are: (3-sitosterol, a - and P-amyrins (both free and as esters), lupeol, tetracyclic triterpene alcohols, small amount of resin acid, tannins saponins, glycosides and a keton (m. p. 83 - 84°C). (Anonymous, 2001)

Many phytochemical studies have been carried out on H. indicus. From the roots ofH. indicus hemidesmol, resin and glucoside, tannin and resin, lupeol, a and P- amyrins, P-sitosterol, lupeol, a-amyrin, lupeol acetate, P-amyrin acetate, hexa triconate acid and lupeol octacosonate, a coumarino lignoid like hesmidesmine, hemidesmin-1 and hemidesmin-2 were isolated. The constituents of oil obtained from the roots of H. indicus contains 80% crystalline matter, glucose, hemidesmol, hemidesterol, 2-hydroxy-4-methoxy benzaldehyde, resin acid, glucoside, sterol and tannins. (Austin, 2008)

Roots of H. indicus was reported to contain steroid, terpenoid, flavonoid and saponin; benzoic acid, 2-hydroxy-4-methoxy benzenoid; Coumarin derivatives namely hemidesmin-1-coumarin and hemidesmin-2- coumarin; a-amyrin triterpene, P-amyrin triterpene and benzaldehyde, 2-hydroxy-4-methoxy benzenoid; 2-hydroxy- 4- methoxybenzaldehyde which is responsible for its aromatic nature, was found to be >90% in their volatile oil, which was isolated from both, fresh and dried roots of different origin. Dried twigs contain a pregnane ester diglycoside desinine (Austin, 2008).

2. Stem:

Glycosides like incucine and hemidine were isolated from stem. The benzenoid derivatives such as benzaldehyde, 2-hydroxy-4-methoxy benzenoid, benzaldehyde, 3-hydroxy-4-methoxy benzenoid and benzaldehyde, 4-hydroxy-3- methoxy benzenoid are reported to present in the stem. The hexane soluble portion of ethanol extract of stem was yielded lactone, lupanone, A12-dehydrolupanyl-3-P- acetate, A12-dehydro lupeol acetate, 4-hydroxy-3-methoxy benzaldehyde. Chloroform and alcohol extracts of stem has two pregnane glycosides, hemidescine

A Study of the (BefiaviouraC and!^europliarmacolbgicaC effects of some indigenous ptants. 57 Cfiapter-2 ^view offiterature

and emidine. Oligoglycosides, indicusin and medidesmine, hemisine and desmine were isolated from the plant (Deepak et al., 1997).

Various steroidal compounds are also found in H. indiucs. 0.0004% of calogenin-3-o-p-D-digitoxopyrano steroid, side-desinine steroid, 0.0009% of desmmine steroid, emidine and hemidescine steroids, 0.0004% of hemidine steroid and hemisine steroid are reported from the stem. It also contains 0.0007% of lup-12- en-21 -28-olide, 3-keto-triterpene, 0.01 % of lup-12-en-3-p-ol acetate triterpene, 0.00666% of lupanone triterpene, 0.03333% of lupeol acetate triterpene and 0.03333% of p-sitosterol. The presence of 0.0008% of medidesmine steroid and 0.2666% of palmitic acid, a lipid in the stem from India was reported (Deepak et al., 1997).

The presence of alkaloids in the stem and root were reported. Also the absence of pyrrolizidine alkaloids in the stem and roots was reported. The presence of tannins, steroids, triterpenoids and carbohydrates was also reported. Two pregnane glycosides isolated were denicunine (calogenin 3.o-3-o-methyl-P-D- fucopyranosyl- (1 ->4)-o-P- D-oleandropyranosi de) and heminine (calogenin 3-o-P-D-cymaropyranosyl-(l->4)-o- P-D-digitoxo-pyranoside). (Austin, 2008)

3. Leaves:

2.50% of tannins were present in the leaves. Coumarinolignoids like hemidesminine, hemidesmin, hemidesmin 1 and hemidesmin 2 are new and rare group of naturally occurring compound with cytotoxic and anti-hepatotoxic properties. Further it also contained flavonoids viz., hyperoside and rutin. (Austin, 2008)

4. Flowers:

The flavanoid glycosides identified in the flowers of H. indicus were hyperoside, isoquercitin and rutin. It was also reported the presence of iso-quercitrin flavonoid and rutin flavonoid in the flowers from India. (Austin, 2008)

5. Entire plant:

The entire plant of H. indicus from India contains indicusin steroid and six pentacyclic triterpenes including two oleanenes, which were identified as olean-12- en-21 p-yl acetate and olean-12-en-3a-yl acetate, three ursenes were characterized as

Jl Study oftfie (BefiaviouTaCaiu£7{mropfiarmacoCogica[ effects of some indigenous plants. 58 Cfiapter-2 ^view of literature < ^ I 16 (17)-seco-urs-12, 20 (30)-dien-18- a H-3B-yl actetate, urs-20 (30)-en-18 -p H-3 p- yl acetate and 16 (17)-seco-urs-12, 20 (30) dien-18-a H-3p-ol and a lupene formulated us lup-l,12-dien-3-on-21-ol including a known compound, p-amyrin acetate, on the basis of spectroscopic techniques and chemical means. (Austin, 2008) 2.6.5 Medicinal properties and traditional uses:

The drug has long enjoyed as reputation as tonic, alternative, demulsent, diaphoretic, diuretic and blood purifier. It is employed in nutritional disorders, syphilis, chronic rheumatism, gravel and other urinary diseases and skin affections. It is administered in the form of powder infusion or decoction as syrup. It is also an ingredient of several medicinal preparations. It is used as a substitute for sarsaparilla and employed as vehicle for patsium iodide and for purpose for which sarsaparilla is used. Syrup is used as a flavouring agent and in the preparation of sherbet which is reported to have cooling property. Milky latex of the plant is used in Travencore, for reliving inflammation in the eye. Ether extract of root exerts some inhibitory effect on growth of Escheresia coli. The leaves are chewed and are said to be refreshing. (Anonymous, 2001; Austin 2008)

1. Root:

The roots are used as antipyretic, anti-diarrhoeal, astringent, blood purifier, diaphoretic, diuretic, refrigerant and tonic (Anonymous, 1986 & 1997; Nadkami, 1989). Roots are usefiil in biliousness, blood diseases, dysentery, diarrhoea, respiratory disorders, skin diseases, syphilis, fever, leprosy, leucoderma, leucorrhoea, itching, bronchitis, asthma, eye diseases, epileptic fits in children, kidney and urinary disorders, loss of appetite, burning sensation and rheumatism (Chopra et al., 1956; Kirtikar and Basu, 1980; Anonymous, 1986; Nadkami, 1989). Root bark is used to cure dyspepsia, loss of appetite, nutritional disorders, fever, skin diseases, ulcer, syphilis, rheumatism and leucorrhoea (Nadkami, 1989).

2. Stem:

Stem of H. indicus is used as diaphoretic, diuretic, laxative and in treating brain, liver and kidney diseases, syphilis, gleet, urinary discharges, uterine complaints, leucoderma, cough and asthma (Kirtikar and Basu, 1980).

Jl Study oftfie

3. Leaves: Leaves are useful in vomiting, wounds and leucoderma (Kirtikar and Basu, 1980).

4. Flower: Flowers are reported as antihypertensive, anti-inflammatory, antioxidant, lox-inhibitor, antiatherogenic (Kirtikar and Basu, 1980)

5. Bark: Bark is effective in dyspepsia, loss of appetite, nutritional disorders, fever, skin diseases, ulcer, syphilis, rheumatism, leucorrhoea (Kirtikar and Basu, 1980)

2.6.6 Ethnobotanical studies: (Austin 2008)

Ethnobotanical studies on H. indicus revealed its benefits towards various ailments, like scorpion sting, snake bite, fever and as a blood purifier. It has cooling effect and used in venereal diseases inclupding gonorrhoea, stomach ulcer, diabetes and fever to increases lactation in mothers, spermatorrhoea, biliousness and headache. (Austin, 2008)

Root decoction is useful for curing high fever and skin diseases. The rind of the root is chewed for sore mouth. Fresh root paste with neem oil would be applied on scalp of children for development of skull bones to enable carrying head-loads in adult age. The root is used to make sweet smelling drink, which is used in the place of coffee and tea. (Austin, 2008)

The dried entire plant is used for skin diseases. It is used for postpartum recovery and also in diarrhoea and to improve appetite. This is also used for impotency and to reduce body heat, as a stimulant and as food. This is said to increase blood circulation and act as a cure for diarrhea. (Austin, 2008)

The roots are peeled and eaten raw as a blood purifier and as cooling beverage and for treating skin diseases. It is taken orally, during the menstrual period to treat leucorrhoea and also as a body tonic. With black pepper, it is used for fevers of long duration and with milk is taken for anemia. This is used as anti-venom. Decoction taken thrice daily checks menorrhagia. It is also used as anti-rheumatic, diuretic, anti­ inflammatory and to treat snake bite. Externally it is applied to provide relief from scorpion stings. This is also used for venereal diseases and as blood purifier, to cure stomach pain and diarrhoea. A decoction with Elephantopus scaber, H. indicus and P. nigrum are used for gonorrhoea. This is also used for skin affections, syphilis and as a tonic. With honey, the fi-esh roots are used for health and vitality. Along with the

A Study of the (BehaviouraC and ^europRarmacobgicaC effects of some indigenous pbnts. CHapter-Z ^view offiterature

woods of Acacia sundra, it is used to make a soft, nourishing beverage to promote youthfulness, health and vitality. (Austin, 2008)

2.6.7 Microbiological studies:

Aqueous extract at 410 mg/ml (IC50), methanolic extract at 200 mg/ml (IC50) and 50% methanolic extract at 320 mg/ml (1C50) was active against Streptococcus mutans. It was effective against C. diphtheriae, D. pneumoniae, S. aureus, S. pyogenes, S. viridans, M. canis, M. gypseum, Phialophora jeanselmei, Piedraia hortae and T. mentagrophytes. It was found to be effective against fungus like Microsporum canis, M. gypseum, Phialophora jeanselmei, Piedraia hortae, Trichophyton mentagrophytes and keratinophilic fungi. (Austin, 2008)

Ethanolic extract (95%) was effective against Corynebacterium diphtheriae, Diplococcus pneumoniae, Staphylococcus aureus. Streptococcus pyogenes and Streptococcus viridans. Ethanolic (95%) and aqueous extracts was effective against yeast like Candida albicans and C. tropicalis. (Austin, 2008)

Chloroform extract of/f. indicus possessed bioactive principles and MIC was found to be 75 mg among vegetative and flowering seasons whereas MLC was found to be 75 mg for flowering season sample and 100 mg for vegetative seasons. The activity is due to the tritepenoid or saponins fractions present in it. The methanolic and chloroform extracts of//, indicus were effective against S.flexneri, least effective against S. dysenteriae and moderately effective against the other enterobacterial strains. (Austin, 2008)

Helicobactericidal activities of various extracts against Helicobacter pylori were found to be comparable with standard antibacterials. Flowering season samples of H. indicus had effective bioactive principles against H. pylori. The results were comparable with standard antibacterials like amikacin, tobramycin, gentamycin, norfoxacin, ciprofloxacin and co-trimoxazole. (Austin, 2008)

H. indicus demonstrated relatively high activity against ESpL- producing multi-drug resistant enteric bacteria, when fractionated into acetone, ethyl acetate and methanol. Further, in vitro haemolytic activity on sheep erythrocytes demonstrated no haemolysis. The glycosides present in H. indicus root inhibits S. typhimurium induced pathogenesis, by reducing bacterial surface hydrophobicity and the presence of hexose, hexosamine, fucose and sialic acid etc. might mimic, host cell receptor

A Study oftfie

saccharides and thereby blocking the bacterial ligands from binding to the host cells. (Austin, 2008)

Antiviral activity (against Ranikhet), Antifilarial, the nematocidal activity {Toxocara canis) and Plaque formation suppressant activity were evident for H. indicus. (Austin, 2008)

2.6.8 Pharmacological studies:

1. Antinociception:

Oral administration of the 25-100 mg/kg extract revealed dose-dependent antinociceptive effect in all the models for antinociception viz. acetic acid induced writhing test, formalin induced paw licking test and hot plate test in mice and it blocked both the neurogenic and inflammatory pain and the nociceptive activity was comparable with the reference drug. The results indicate that alcoholic extract of H. indicus R. Br. possesses a significant antinociceptive activity. The activity can be related with the significant phytochemicals such as triterpenes, flavonoids, and sterols reported in the root extract. (Austin, 2008)

2. Anti-inflammatory:

The ethyl acetate extract of roots of H. indicus exhibited significant anti­ inflammatory activity in both acute and sub-acute inflammation as revealed by significant inhibition of inflammation induced by carageenin, bradykinin, s-hydroxy tryptamine, employing granuloma pouch and cotton pellet implantation methods in rats. However, it was found less active than phenyl butazone or p-methasone, against granuloma pouch and cotton pellet implantation. It is ineffective in dextran induced inflammation. (Austin, 2008)

3. Antiulcer:

The antiulcerogenic property of aqueous ethanolic extracts of the roots of H. indicus was evaluated in modified pyloric ligated (shay) rat model and aspirin- induced ulcerogenesis in pylorus ligated rat. Roots collected during flowering season were found to be more effective than that collected during vegetative seasons. It exerts mucoprotective effect comparable with standard drugs ranitidine and omeprazole. The doses of 300 and 450 mg/kg were effective in the pyloric ligated, cysteamine, and aspirin induced ulcer models in rats. The antiulcerogenic effect of i/.

^ Study of the (Behavioural and 9{europfiarmacotogicaC effects of some indigenous plants. 62 Cfiapter-2 ^view of Citerature

indicus was mainly because of its high mucoprotective activity, depicted by a selective increase in prostaglandin content. H. indicus, therefore, provides another alternative for ulcer treatment. It aims at enhancing the defensive factors so that the normal balance between offensive and defensive factors is achieved. (Dharmani, 2006)

4. Hepatotonic and hepatotoxic:

It has been observed that oral administration of ethanolic (70%) extract of//. indicus at a dose of 100 mg/kg, for 15 days, significantly prevented rifampicin and isoniazid-induced hepatotoxicity in rats. Both in single (50, 100 and 200 mg/kg) and multiple doses (50 and 100 mg/kg for 7 days) of aqueous extract H. indicus were demonstrated the hepatoprotective activity against ethanol-induced oxidative stress and liver damage suggesting enhanced antioxidant defense mechanism. (Austin, 2008)

Methanolic extract of H. indicus at a dose of 250 mg/kg by oral route was effective in carbon tetra chloride induced hepatic damage whereas 500 mg/kg was effective in paracetamol induced hepatic damage. Biochemical parameters like serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP), total and direct bilirubin were within normal range and the results were comparable with standard hepatoprotective agent silymarin at a dose of 100 mg/kg. On the contrary, ethanolic (50%) extract of// indicus was produced hepatomegaly, which was confirmed by biochemical and histopathological studies. The reason may due to the extraction methodology, which might be due to a principle present in this type of extraction. (Austin, 2008)

The effects of ethanolic root extract of H. indicus on experimental liver damage was evaluate for its hepatoprotective effects against hepatotoxicity induced in rats by ethanol at a dosage of 5 g/kg body weight for 60 days. The animals were monitored for food intake and weight gain. The liver was analysed for the degree of lipid peroxidation using thiobarbituric acid reactive substances (TBARS) and antioxidant status using the activities of glutathione-depedendant enzymes. The degree of liver damage was analysed using serum marker enzyme activities, the total protein, albumin, globulin, ceruloplasmin and liver glycogen contents, and the A/G ratio. The fourier transform infrared spectra (FT-IR) of the liver tissues were recorded

A Study oftfie (BefiaviouraC and^{euTopfiarmacoCogicaC effects of some indigenous pCants. 63 Cfiapter-2 (Rfview of Citerature

in the region of 4000-400 cm''. The ethanol-fed rats showed significantly elevated liver marker enzyme activities, lipid peroxidation levels and reduced antioxidant levels as compared to the control rats. (Saravanan and Nalini, 2007a)

The oral administration of 500 mg/kg body weight of//, indicus for the last 30 days of the experiment resulted in an increased food intake and weight gain, decreased TBARS levels, near normal levels of glutathione-dependent enzymes, increased total protein, albumin, globulin and liver glycogen contents, an increased A/G ratio, and decreased liver marker enzyme activities and ceruloplasmin levels. The relative intensity of the liver FT-IR bands for the experimental groups were found to be altered significantly (p< 0.05) compared to the control samples. For the group that had H. indicus co-administered with ethanol, the intensity of the bands was near normal. They also reveled that the results of the FT-IR study correlated with their biochemical results. (Saravanan and Nalini, 2007a)

The inhibitory activity of ethanolic root extract of H. indicus and its active principle 2-hydroxy 4-methoxy benzoic acid (HMBA) were evaluated on liver fibrotic markers and characteristics such as collagen content, matrix metalloproteinases (MMPs) 2 and 9 in ethanol-fed rats. Ethanol administration significantly increased the levels of liver collagen and hydroxy proline content, cross-linked fluorescence, shrinkage temperature and lipid peroxidation and significantly decreased the solubility of liver collagen and the ascorbic acid content when compared with control rats. On treatment with H. indicus and HMBA the ethanol-fed rats showed significantly reduced levels of liver collagen and hydroxyproline content, cross-linked fluorescence, shrinkage temperature and lipid peroxidation and enhanced solubility of liver collagen and ascorbic acid levels when compared with untreated ethanol-fed rats. MMPs were extracted from the liver of control, H. indicus-treated, HMBA-treated, ethanol-administered, ethanol with H. /«J/cM5-coadministered and ethanol with HMBA-coadministered rats. The inhibition was analyzed by gelatin zymography and the percentage of expression was determined by a gel documentation system. The activities of MMPs 2 and 9 were significantly increased in ethanol-supplemented rats. Cotreatment of H. indicus/VMBA with ethanol showed significantly decreased activities of these enzymes when compared with those of the untreated rats. H. indicus/HMBA alone treatment showed no such significant alterations. Thus it was revealed the strong inhibitory activity of H. indicus and HMBA on the quantitative

Ji Study oftfie (Be/iatnourafamfyfeuropfiarmacolbgicaf effects of some indigenous plants. 64 Cfiapter-2 ^view of Citerature I # and qualitative properties of hepatic collagen and also MMPs involved in the extracellular matrix degradation during ethanol intoxication. (Saravanan and Nalini 2007c) 5. Diuretic:

The alcoholic and steam distilled extracts of roots of H. indicus had no significant diuretic activity, whereas aqueous extract caused a slight increase in urinary flow in rats, but not in dogs. The H. indicus as an adjunct therapy along with aminoglycosides, such as gentamicin was able to reduce nephrotoxicity, caused by them. (Austin, 2008)

6. Antidiarrhoeal:

The methanolic extract at a dose of 500-1500 mg/kg elicited antidiarrhoeal activity which was effective than the standard antidiarrhoeal drug lomotil and the activity was due to inhibition of intestinal motility and its bactericidal activity (Das et al., 2003).

The aqueous extract at a dose of 50-200 mg/kg increases absorption of water, Na"^ and K"^ from the jejunam, on the contrary ethanolic extract decreased. H. indicus root in the form of suspension in water (10 mg/ml) containing 15.5 mM NaCl, 3 mM KCl and 12 mM glucose, when injected into the ligated jejunal sac (1 ml/sac) of rat, increased the absorption of water, Na* and K"*^ (but not glucose) from the sac. This bioactivity was present in the water extract (5 or 10 mg/sac) of the root and not in the hexane extract. In contrast, the ethanol extract decreased the absorption of water and electrolytes from the jejunal sac. The effect of water extract was not affected by heat at 100°C for 30 min. Intraperitoneal administration of the water extract (50 to 200 mg/kg) was devoid of any significant effect on the jejunal absorption. Neither the root suspension nor the water extract (125-500 mg/kg) showed any significant anti-ulcer and diuretic activities in rats. The intestinal motility was also not influenced by the root (water extract) when tested in mice. The present study indicates that H. indicus root powder or its water extract can be incorporated in oral rehydrating salt solution (ORS) for increasing its anti-diarrhoeal efficacy. (Evans et al., 2004)

A Study of the (Beliaxnouraf andy^europfiarmacolbgicaf effects of some indigenous pCcmts. 65 Cfiapter-2 ^view ofCiterature =• 7. Antivenom:

The methanolic extract ofH. indicus significantly neutralized by viper-venom induced lethality and haemorrhagic activity in albino rat and mouse. Maximum neutralization was achieved (Alam et al., 1996).

The lupeol acetate from the methanolic extract of//, indicus which was found to neutralize venom induced action of Daboia russellii and Naja kaouthia on experimental animals. It could significantly neutralize lethality, haemorrhage, defibrinogenation, edema, PLA2 activity induced by D. russellii venom. It also neutralized TV. kaouthia venom induced lethality, cardiotoxicity, neurotoxicity and respiratory changes in experimental animals. (Chatterjee et al., 2006)

A compound 2-hydroxy-4-methoxy benzoic acid isolated and purified from the methanolic extract of Indian medicinal plant H. indicus were shown to possess antisnake venom activity. Rabbits immunized with Vipera russellii venom in the presence and absence of the compound along with freund's complete adjuvant produced a precipitating band in immunogel diffusion and immunogel electrophoresis. The venom neutralizing capacity of this antiserum showed positive adjuvant effects as evident by the higher neutralization capacity (lethal and hemorrhage) when compared with the antiserum raised with venom alone. The pure compound potentiated the lethal action neutralization of venom by commercial equine polyvalent snake venom antiserum in experimental models. These observations raised the possibility of the use of chemical antagonists (from herbs) against snake bite, which may provide a better protection in presence of antiserum, especially in the rural parts of India. In addition the 2-hydroxy-4-methoxy benzoic acid, isolated and purified from the methanolic extract possessed potent anti-inflammatory, antipyretic and antioxidant properties. It neutralized inflammation induced by Vipera russelli venom in male albino mice and reduced cotton pellet-induced granuloma. In addition, it also produced a significant fall in body temperature in yeast-induced pyrexia and did not change normothermic body temperature. The compound effectively neutralized viper venom-induced changes in serum phosphatase and transaminase activities and neutralized free radical formation as estimated by TBAPS and superoxide dismutase activities, which helps in neutralizing the venom. (Alam et al., 1998a)

A Study of the (BefiaxnouraCamfT^europfiaimacolbgicaf effects of some indigenous pCants. 66 Ctiapter-2 ^view of Citerature

The venom neutralizing capacity of this antiserum in rabbits immunized with Vipera russellii venom showed positive adjuvant effects as evident by the higher neutralization capacity (lethal and hemorrhage) when compared with the antiserum raised with venom alone. It potentiated the lethal action neutralization of venom by commercial equine polyvalent snake venom antiserum in experimental models. These observations raised the possibility of the use of chemical antagonists (from herbs) against snake bite, which may provide a better protection in presence of antiserum, especially in rural parts of India. (Alam et al., 1998b).

8. Antileprotic:

Ethanolic (95%) extract was found to cause stimulation of delayed type cutaneous hypersensitivity. The aqueous extract of H. indicus was given orally at a concentration of 2% of diet in mice was active against Mycobacterium leprae. The mice were infected with the test organism taken from leprosy patients. It delayed the cutaneous hypersensitivity stimulation at a dose of 100 mg/kg. It also possessed immuno-modulator as well as immuno-suppressant activities at 100 mg/kg. Phagocytosis was also decreased at 100 mg/kg. (Austin, 2008)

9. Anticancer:

Topical application of H. indicus resulted in significant protection against cutaneous tumourogenesis. Topical application of plant exfract at a dose level of 1.5 and 3.0 mg/kg in acetone prior to that of TPA treatment resulted in significant inhibition of oxidative stress. The level of lipid peroxidation was significantly reduced. In addition, depleted levels of glutathione and reduced activities of antioxidant enzymes were restored, respectively which indicates its potent chemopreventive nature in skin carcinogenesis. It has a strong dose-dependent cytotoxic activity and anti-hepatocarcinogenic potential by not only inhibiting diethylnifrosamine mediated expression of glutathione s-transferase P form, but also the carcinogen mediated development of overt tumors and histopathological changes leading to tumor development. (Austin, 2008)

10. Chemopreventive:

H. indicus is an effective chemopreventive agent in skin and capable of ameliorating eumene hydroperoxide-induced cutaneous oxidative stress and tumor promotion, in a dose dependent manner from 1.5-3.0 mg/kg. H. indicus suppressed

A Study oftfie

Antioxidant activity of methanolic (50%) extract of H. indicus root bark in several in vitro and ex vivo models were evaluated. Further, preliminary phytochemical analysis and TLC fingerprint profile of the extract was established to characterize the extract which showed antioxidant properties. The in vitro and ex vivo antioxidant potential of root bark of//, indicus was evaluated in different systems viz. radical scavenging activity by DPPH reduction, superoxide radical scavenging activity in riboflavin/light/NBT system, nitric oxide (NO) radical scavenging activity in sodium nitroprusside/greiss reagent system and inhibition of lipid peroxidation induced by iron-ADP-ascorbate in liver homogenate and phenylhydrazine induced haemolysis in erythrocyte membrane stabilization study. ITie extract was found to have different levels of antioxidant properties in the models tested. In scavenging DPPH and superoxide radicals, its activity was intense (EC50 = 18.87 and 19.9 microg/ml respectively) while in scavenging NO radical, it was moderate. It also inhibited lipid peroxidation of liver homogenate (EC50 = 43.8 microg/ml) and the haemolysis induced by phenylhydrazine (EC50 = 9.74 microg/ml) confirming the membrane stabilization activity. The free radical scavenging property may be one of the mechanisms by which this drug is effective in several free radical mediated disease conditions. (Austin, 2008)

Methanolic extract of H. indicus roots was inhibited lipid peroxidation and scavenges hydroxyl and superoxide radicals in vitro. 50% inhibition of lipid peroxide formation was achieved at 217.5 )iig/ml, scavenges hydroxyl radicals at 73.5 |j,g/ml and superoxide radicals at 287.5 ^g/ml respectively. Intravenous administration at a dose of 5 mg/kg for rabbits delayed plasma recalcification time and enhanced the release of lipoprotein lipase enzyme significantly. The extract also inhibited ADP- induced platelet aggregation in vitro (50-250 jAg), which was comparable with commercial heparin. (Austin, 2008)

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The antioxidant effect of the ethanolic extract of H. indicus root in rats was studied with ethanol-induced nephrotoxicity. Administering 5 g/kg body weight/day of ethanol for 60 days to male Wistar rats resulted in significantly elevated levels of serum urea, creatinine and uric acid as well as kidney thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH) and conjugated dienes (CD) as compared to those of the experimental control rats. Decreased levels of kidney superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C and vitamin E were also observed on alcohol administration as compared with those of the experimental control rats. The extract was administered at a dose of 500 mg/kg body weight/day for the last 30 days of the experiment to rats with ethanol-induced kidney injury, which significantly decreased the levels of serum urea, uric acid and creatinine as well as kidney TBARS, LOOH and CD and significantly elevated the activities of SOD, CAT, GPx, GSH, vitamin C and vitamin E in kidney as compared to that of untreated ethanol-administered rats. Histopathological observations also correlated with the biochemical parameters. Thus, the data indicate that treatment with the extract offers protection against free radical- mediated oxidative stress in kidney of animals with ethanol-induced nephtrotoxicity. (Saravanan and Nalini, 2007b)

12. Toxicity studies:

During the toxicity studies the dried stem o^H. indicus was fed to albino rats at a dose of 25% in their diet for ten days. Histopathological studies showed hepatotoxic activity. There were diffuse hydropic degeneration and focal hepatocellular necrosis. Toxicity was seen in the liver, but not in the lungs or kidney. In quantitative toxicity assessment by oral route LD50 was found to be 2500 mg/kg. (Austin, 2008)

2.6.9 Cell culture studies:

The antiproliferative activity of extracts of H. indicus were analysed on different human cell lines, including erythroleukemia K562, B-lymphoid raji, T- lymphoid jurkat and erythroleukemia HEL cell lines by electrophoretic mobility shift assay (EMSA). It was found that low concentrations inhibit the interactions between nuclear factors and target DNA elements mimicking sequences recognized by the nuclear factor kappa B (NF-kappa B). This activity along with its tumor cell growth

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might be a source for anti-tumor compounds, while extracts inhibiting NF-kappa B/DNA interactions with lower effects on cell growth, could be of interest in the search of compounds active in inflammatory diseases, for which inhibition of NF- kappa B binding activity without toxic effects. (Austin, 2008)

2.6.10 Miscellaneous:

The antiatherogenic effect of an herbal formulation Caps HT2 was evaluated by evolving its antioxidant, anticoagulant, platelet antiaggregatory, lipoprotein lipase releasing, anti-inflammatory and hypolipidaemic activities in rats. It was found to scavenge superoxide and hydroxyl radicals; the IC50 required being 55.0 and 610.0 p,g/ml, respectively. Lipid peroxidation was inhibited by 48.5 mg/mL. Intravenous administration at a dose of 5 mg/kg delayed plasma recalcification time in rabbits and enhanced the release of lipoprotein lipase enzyme. It also inhibited ADP induced platelet aggregation in vitro, which was comparable to commercial heparin. It also possessed significant anti-inflammatory actions in acute and chronic inflammations induced by carrageenan and formalin, respectively in rats. Its hypolipidaemic effect in diet-induced hyperlipidaemia in rats was elucidated at a dose level of 100, 200, 300 and 400 mg/kg and raised HDL cholesterol levels. The atherogenic index and reduction in body weight indicated its effectiveness against hyperlipidaemia and obesity. Study suggested that it can be suggested for vascular intimai damage and atherogenesis leading to various types of cardiovascular problems. (Austin, 2008)

The effect of 2-hydroxy 4-methoxy benzoic acid (HMBA), the active principle of//, indicus were evaluated on hyper-lipidaemia induced by ethanol, exploring food intake, body weight, and hepatic and plasma lipids and lipoproteins. Rats were given ethanol (5 g/kg, p.o.) daily for 30 days. Subsequently, ethanol-fed rats were given HMBA intra-gastrically at a dose of 200 ^g/kg per day for 30 days. At the end of the total experimental period of 60 days, plasma concentrations of total cholesterol (CHO), triglycerides (TG), lipoproteins (LP), phospholipids (PL), free fatty acids (FFA) and lipoprotein lipase (LPL), and hepatic CHO, TG and PL were measured. Treatment of ethanol-fed rats with HMBA significantly decreased plasma CHO, TG, LP, PL and FFA and hepatic CHO, TG and PL, and increased plasma LPL concentrations compared with values in untreated ethanol-fed rats. Food intake and average body weight at the end of the experimental period were significantly increased by HMBA administration. They were concluded that the administration of

A Study oftHe (BefmviouraC andO^mropfiarmacotbgicaC effects of some indigenous plants. 70 Cfiapter-2 (Rfview offiterature I HMBA decreased lipids and lipoprotein concentrations significantly in an animal model of ethanol-induced hyperlipidaemia. (Saravanan and Nalini, 2007a)

The effect of H. indicus extract on the secretion of immunoglobulin G (IgG) and adenosine deaminase (ADA) activity were investigated from un-stimulated and lipopolysaccharide (LPS) or phytoheameagglutinin (PHA) stimulated human peripheral blood lymphocytes (PBLs). LPS and PHA stimulate specifically, B cells and T cells, respectively. (Kainthla et al., 2006)

The total extract of the raw herb was obtained by methanol: isopropyl alcohol: acetone extraction, and used at 10 - 1000 |ig/ml concentration. Human peripheral blood lymphocytes (PBLs) were isolated, stimulated to proliferate using phytohaemagglutinin (PHA) or lipopolysaccharide (LPS), with and without H. indicus extract. Adenosine deaminase (ADA) activity and immunoglobulin (IgG) secretion from cultured PBLs were studied with the herbal extracts and appropriate controls. The extract stimulated the cell proliferation at 1 mg/ml concentration significantly, after 72 h in culture. Viability of extract-treated PBLs was also maintained after culture. The extract increased the IgG production from cultured PBLs at 1 mg/ml concentration. It also increased the ADA activity of PBLs after 72 h in culture. Thus it has been revealed an immunomodulatory activity of H. indicus. The extract significantly enhanced the cell proliferation in unstimulated human PBLs, highest at 1000 p,g/ml. In the presence of LPS or PHA, the extract (1000 ixg/ml) synergistically increased cell proliferation, compared with LPS or PHA alone. Therefore, the extract might be acting as a mitogen for both B and T cells. The extract has no adverse effect on cell viability when exposed to 72 hours. B cell responses are usually measured by assays of secreted antibodies (IgG, IgM etc.). The extract (1000 i^g/ml) significantly enhanced the IgG secretion from PBLs, in absence or presence of LPS. LPS, which is known to be one of T-cell-independent (TI) antigen, activates B cells and differentiates B cells into IgG secreting cells. The extract (1000 |Ag/ml), when added to LPS-stimulated, as well as unstimulated human PBLs, enhanced the IgG secretion after 72 h in culture. This indicates that extract alone also possess some mitogenic activity, which enhances the IgG secretion from PBLs, similar to LPS alone. Some of the components isolated from H. indicus are ketone, saponins, tannins, sterols, P- sitosterol, stigmasterol, and sarsapic acid. One of these components might add to the mitogenic effect of lipopolysaccharide, which in turn might stimulate the secretion of

Jl Study of the

A comparative clinical study with Indukanta ghirta and Mahatiktaka ghrita for peptic ulcer were carried out, where H. indicus is a major ingredient in Mahatiktaka ghrita. Also studies on Sariva ghanasatva were carried out, which contains H. indicus as a major ingredient was found to be effective against allergic conjunctivitis. It was also found that H. indicus was effective in advanced cases of malignancies like multiple myeloma, adenocarcinoma, squamous cell carcinoma, Hodgkin's lymphoma etc. though not a cure. (Austin, 2008)

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2.7 Hedychium spicatum (H. spicatum)

1.1.\ Family: Zingiberaceae

2.7.2 Synonyms and regional names:

Sanskrit - Amlaharidra, Amlanisha, Durva, Gandapatari, Gandasati, Gandha, Gandhamuli, Gandhamulika, Gandhapalashi, Gandharika, Gandhasati, Gandhavadhu, Gandholi, Haimi, Haridracchadana, Himaja, Himodbhava, Jimutamula, Kachhora, Karbura, Karchura, Karpura, Karpurakachali, Karpurakachali, Prithupalashika, Prthupalasika, Samudra, Sathi, Sati, Saumya, Shadugrantha, Shathi, Shati, Shedwa, Sugandha, Sugandhamula, Sugandhasati, Suvata, Tuni.

Hindi - Gandhapalashi, Kafur-Kachri, Kapurakachari, Kapurkachri, Kapurkachri, Kapurkachur, Sitruti, Sitruti, Kapoor Kachri

Ayurvedic - Shati, Karchur

Unani - Kapoor kachari

Bengal - Ada, Ama, Gandhshati, Shati

Gujarat - Kapurkachari

Panjab - Banhaldi, Bankela, Kachurkachu, khor, saki, shalwi, sheduri

Marathi - Kapurkachari, Sonataka

Tamil - Simaikkichilikkilhangu

Englisli - Abir. Spiked Ginger-Lily

Arebic - Jharanbaja

Urdu - Kapurakachari

Trade name - Kapoor kachri

2.7.3 Parts used: Rhizomes and essential oil from rhizomes

^ Study of the ^ehaviourid and O^eumpharmacotogicat effects of some indigenous ptants. 73 Ctiapter-2 ^view ofCiterature

2.1 A Pharmacognostical studies:

1. Distribution:

H. spicatum commonly known as Kapurkachri, is a perennial rhizomatous herb distributed through the forests; 1200-3200 m. in Guizhou, Sichuan, Xizang, Yunnan, Bhutan, NE India, Myanmar, Nepal, Sikkim, N Thailand. In India distributed in the Himalaya between altitude of 800-3000 m asl. (Anonymus, 2005; Bhatt et al., 2008)

2. Macroscopical characters:

Herbs are terrestrial or epiphytic, with tuberous rhizomes. Pseudostems are erect and leafy. Ligule is conspicuous; inflorescence a terminal spike, densely numerous flowered; bracts imbricate or lax, 1- or more flowered; bracteoles tubular. Calyx is tubular usually split on 1 side, apex truncate or 3-toothed. Corolla is tube long, slender; lobes reflexed at anthesis, linear. Lateral staminodes petaloid are larger than corolla lobes. Labellum sub-orbicular, large, apex usually 2-cleft; claw long or short. Filament usually long, rarely absent; anther dorsifixed, base divaricated; connective appendage absent. Ovary 3-loculed; placentation axile. Capsule globose, 3-valved. Seeds numerous; aril lacerate. (Shu, 2000)

Pseudostems is ca. 1 m. Leaves are sessile or shortly petiolate; ligule entire, 1.5-2.5 cm, membranous; leaf blade oblong or ob-long-lanceolate, 10-40 x 3-10 cm, glabrous or abaxially sparsely villous a long mid vein, base acute, apex acuminate. Spikes to 20 cm, laxly few or densely many flowered; bracts are oblong, 2.5-3 cm, 1- flowered. Flowers are fragrant; Calyx is 2.5-3.5 cm, apex 3-toothed, split on 1 side. Corolla pale yellowish; tube to 8 cm, apex sometimes purplish red; lobes are linear, ca. 2.5 cm, base sometimes purplish red. Lateral staminodes white or becoming yellow, sometimes purplish red, obovate, apex 2-lobed; lobes clawed, apex acute. Labellum yellowish, sometimes purplish red. Filament is pale reddish, shorter than labellum. Capsule is sub-globose, 1.5-2.5 cm in diam., 3-valved; valves ca. 6-seeded. Flowering in Jun-Oct and fruits in Oct-Nov. (Shu, 2000)

Leaves are reaching 30 cm or more, oblong or oblong-lanceolate, very variable in breadth, glabrous. Spike is sometimes 30 cm, dense flowered, bracts large, oblong, obtuse, green, 2.5 - 3.8 X 2 cm broad, 1-flowered; calyx shorter than the bract; Flowers are white ascending and closely imbricate in the type. Corolla tube is 5

A Study of the ^(iaxnotiraC and T^etiropharmacolbgicaC effects of some irufigenous plants. 74 Cfiapter-2 ^view of [iterature

- 6.3 cm; segments 2.5 cm, linear; staminodes 2.5 cm, lanceolate, lip cuneate, deeply bifid, 13-20 mm broad, not at all clawed, lobes 2, rounded; stamen rather shorter than the lip; filament pale red; anther linear, 6 - 8.5 mm. Capsule glabrous, globose. (Shu, 2000)

''m^ -V

Figure 2.4: Hedychium spicatum (Shu, 2000)

Medicinal varieties: Hedychium spicatum var. spicatum and acuminatum (Shu, 2000)

Hedychium spicatum var. spicatum: Spikes arte densely many flowered. Flowers are yellowish. Flowering in Jun-Jul. 2/7 = 34. Forests; 1200-2900 m. Guizhou, Sichuan, Xizang, Yunnan, Myanmar, Nepal, N Thailand.

Hedychium spicatum var. acuminatum: Spikes are laxly few flowered. Flowers are yellowish but apex of corolla tube, base of corolla lobes, lateral staminodes, and labellum purplish red. Flowering in Aug-Oct. Forests; 2000-3200 m. Xizang, Yunnan, Bhutan, NE India, Nepal, Sikkim.

Jl Study of the (BefiaviouraC and O^europliarmacologicaC effects of some indigenous plants. 7C Cfiapter-2 (Rfview of Citerature

2.7.5 Phytochemical studies:

The total phenols, carotenoids and vitamin content in H. spicatum were characterized and quantified and it was observed that total phenolic content varied considerably between two sources (Table 2.2) (Bhatt et al., 2008).

Table 2.2: Carotenoids and vitamin content in H. spicatum in planted and wild source.

Antioxidants Planted Wild

Total phenolics (mg/lOOg) 218 ±0.01 181.8 ±0.02

Xanthophyll (mg/lOOg) 0.23 ±0 1.65 ± 0.1

a-Carotene (mg/lOOg) 6.9 ±0.8 20.5 ±1.2

p-Carotene (mg/lOOg) 19.3 ±2.4 61.8 ±2.8

DL-a-tocopherol(mg/100g) 4.9 ±0.2 1.1 ±0.2

The phenolic content (218 mg/lOOg) was found significantly (p<0.05) higher in one year old planted source as compared to wild ones (181.8 mg/lOOg). The content varied significantly between two sources. While comparing with planted rhizomes, xanthophyll, a-carotene, P-carotene content were found significantly more in the rhizomes of wild source. On the contrary, DL-a-tocopherol was significantly more in planted source (Table 2.2). (Bhatt et al., 2008)

In a phytochemical study of the rhizome essential oils of H. spicatum by means of GC and GC/MS analyses, three different collections (I-III) showed amazing differences in the relative contents of their essential oils. 1, 8-cineole and 10-epi- gamma-eudesmol being identified as markers for samples I and II, whereas terpin-4-ol and sabinene being the major compounds in sample III. (Joshi et al., 2008)

2.7.6 Medicinal properties and traditional uses:

H. spicatum find use in indigenous medicines for a number of ailments. (Kirtikar and Basu, 2003; Chopra et al., 1969). Rhizome of ^. spicatum is used for asthma, bronchitis, blood purification, gastric disorders and as antiemetic.

^ Study of the ^ehavburai and O^eutopharmacotogicaC effects of some indigenous plants. 76 Cfiapter-2 ^view of Citerature

The rhizome is considered as stomachic, carminative, stimulant and emmenagogue and useful for liver complaints, diarrhoea, food poisoning and various other diseases. The crude extract of rhizome is used as a major ingredient in making syrup and tablets with brand name Vomicure® and Vominil® respectively. Recently the crude extract of the rhizome has been used in the preparation an anticancerous drug. (Bhatt et al., 2008)

1. Rhizome:

Liver complaints, indigestion and in poor circulation due to thickening of the blood. Nausea, vomiting, bronchial asthma, halitosis, diminished appetite, hiccups, local inflammation. Carminative, stimulant and a tonic, antiasthmatic agent. Counteracts bad mouth taste and smell. Vasodilator alleviates spasms, hypoglycemic, antiasthmatic, antiinflammatory and stimulant; Vasodialator effect on coronary vessels, hypotensive, anti spasmodic effect on smooth muscles.

Rhizome of H. spicatum are aromatic, acidic, bitter, pungent, carminative, stomachic, stimulant, expectorant, anti-asthmatic, antiseptic and anti-inflammatory, in asthma, bronchitis, vomiting, dyspepsia, insect repellent properties

2. Essential oil:

Anthelmintic, antimicrobial and mild tranquilising effect of short duration.

3. Rootstock:

Carminative, emmenagogue, expectorant, stimulant, stomachic and tonic, in local inflammatory, nauseas, asthma, bronchitis, hiccups, and in pain.

2.7.7. Ethnobotanical studies:

The presence of phenolic content, xanthophylls, a-carotene, P-carotene and DL-a-tocopherol in H. spicatum was evident. Phenolics, carotenoids and vitamins are well known for its antioxidant activity and repeatedly been used as natural antioxidants in fruits, vegetables and other plants. For example, caffeic acid, ferulic acid, and vanillic acid are widely distributed in the plant kingdom. Rosamarinic acid, an important phytochemical has been found to be a potent active substances against human immunodeficiency virus typel (HIV-1). Carotenoids are a group of natural pigments, widely acceptable to consumers being present in natural foods and are readily metabolized. The hydrocarbon carotenoids have pro-vitamin-A activity and

A Study oftfie (BefiaviouraC and 9{mTopRarmacoliogicaC effects of some indigenous plants. 77 Cfiapter-2 ^view of fiterature

the oxygenated carotenoids or xanthophylls are possibly linked to a lower risk of cancer. (Bhatt et al., 2008)

Studies have shown that carotenoids may play an important role in the prevention of age related macular degeneration (AMD), p-carotene has proved to prevent peroxidation caused by singlet oxygen and also by scavenging free radicals. Likewise, a-tocopherol is known to have a number of biological activities such as immune stimulation, inhibition of nitrosamine formation and alteration of metabolic activation of carcinogens. The major protective function of the vitamins against cancer is the scavenging of reactive oxygen metabolites (ROMs). Recent reports highlighted the role of a-tocopherol in lowering the lipid oxidation in human body and counteract the pro-oxidative effect with other compound like ascorbate and combination of ascorbate and P-carotene. (Bhatt et al., 2008)

2.7.8 Microbiological studies:

The extracts from rhizomes of Hedychium spicatum were tested for their antibacterial and antifungal activity. Essential oil, petroleum ether and chloroform extracts showed inhibitory activity against Gram (+) and Gram (-) bacterial cultures, including a strain of methicillin and vancomycin resistant Staphylococcus aureus and fungal cultures. (Bisht, 2006) The essential oil extracted from rhizomes of H. spicatum was tested for in-vitro pediculicidal activity. At 5%, 2% and 1% concentration the essential oil showed more significant activity than 1% permethrin based product. (Jadhav et al., 2007)

The antimicrobial screenings of the oils was done by the paper-disc method against Staphylococcus aureus, Shigella flexneri, Pasteurella multocida, Escherichia coli, and Salmonella enterica enterica, and the respective minimum-inhibitory- concentration (MIC) values were determined. (Joshi et al., 2008)

2.7.9 Pharmacological studies:

1. CNS studies:

The essential oils of H. spicatum were investigated for their pharmacological effect on central nervous system. The essential oils were obtained by steam distillation of rhizomes. The essential oils were administered as emulsions made with

Jl Study of the (BefiaviourafandJ^europfiarmacolbgicaCejfects of some imfigenous plants. 78 Cfiapter-2 ^view of Citerature % =• 3% aqueous polysorbate-80. The signs of central nervous system depression were observed in rats treated with essential oils. The essential oil of H. spicatum produced decrease in spontaneous motor activity and mild sedation. The response to pain and touch stimuli was reduced. The awareness and alertness were markedly affected but the righting reflex was only slightly affected. The treated animals moved with unsteady gait and ptosis was marked. The peak actions of the essential oil were recorded 30 min after their administration and the effect lasted for 3 hrs. No any mortality was observed in the given doses. The essential oil of//, spicatum produced significant effect on secondary conditioned avoidance response (SCR) and conditioned avoidance response (CAR) of trained rats. The effect was at its peak 30 mm after the treatment. 80% of animals showed blockade of SCR, whereas CAR was blocked in 40% of animals. The essential oil of H. spicatum markedly affected the rotarod performance of the trained animals, the number of animals falling down from cylinder being 40 and 70% with 100 mg/kg and 200 mg/kg dose respectively. The peak effects were produced after 30 min of their administration and the duration of action was about 4 h. The essential oil potentiated pentobarbitone induced hypnosis, the mean sleeping time being increased considerably. The essential oil also produced marked analgesia and the duration of effect lasted for about 2 h. The effect, however, was less compared to morphine. The essential oil of H. spicatum produced only slight hypothermic effect in the rats. The effect with 100 mg/kg dose started with 30 min and a maximum fall of 1°C was observed after 1 h. The higher dose (200 mg/kg) caused the maximum fall of 1.2''C within 30 min and lasted for 1 to 2 h. The essential oil (200 mg/kg) slightly delayed the onset of action of amphetamine but the mortality remained unaffected. (Dixit et al., 1979) 2. Analgesic and anti-inflammatory:

Alcoholic extract of rhizome of H. spicatum was found to possess significant anti-inflammatory activity in carrageenin-induced hind paw oedema. It also produced analgesic activity in acetic acid-induced writhing movements in mice and Randall- Selitto assay in rats. (Tandan et al., 1997)

Jl Study of the (BeRavhuraC andT^europftarmacobgicd effects of some indigenous plants. 79 Cfiapter-2 ^view of Citerature •= 3. Anticancer:

The phytochemical investigation of chloroform extract of the rhizomes of H. spicatum led to the isolation of two new labdane-type diterpenes, compounds 1 and 2 along with five known compounds (3-7). Their structures were established on the basis of NMR (ID and 2D) and mass spectroscopic analysis. In addition, all the isolates were tested for their cytotoxicity against the Colo-205 (Colo-cancer), A-431 (skin cancer), MCF-7 (breast cancer), A-549 (lung cancer) and Chinese hamster ovary cells (CHO cell lines). Two new compounds 1 and 2 were shown good cytotoxic activity. (Reddy et al., 2009)

4. Antioxidant:

Essential oil of rhizomes of H. spicatum was studied for their antioxidant activities by different methods, including their effect on the chelating properties of Fe^"", DPPH radical-scavenging activity, and reducing power. The rhizome essential oils of H. spicatum exhibited moderate-to-good Fe^"^ chelating activity. H. spicatum from collection site III showed a completely different DPPH radical-scavenging profile than the samples from the other collection sites. (Joshi et al., 2008)

^ Sttidy of the