Pharmacognosy Lecture 7AB Sherif S. Ebada, Ph.D.
Contact information: Assoc. Prof. Dr. Sherif S. Ebada Pharmaceutical Chemistry Dept. Office hours: Tuesdays and Thuresdays: 10:00 am–12:00 pm E-mail: [email protected]
1 2 Herbs
Content: • Introduction to herbs. • Herbs containing Volatile oil: e.g. Mentha & Thyme. • Herbs containing Alkaloids: e.g. Lobelia & Catharanthus. • Thallophytes: e.g. Ergot & Ephedra.
3 Definition of Herb • In Botany: a plant with non-woody & non permanent stem, which dies after fruiting.
• In Pharmacognosy: it is a drug formed of a tender part of the plant axis (stem) together with the leaves, flowers & fruits.
• Examples: 1. Upper part of the aerial shoot i.e. tops e.g. Cannabis. 2. Whole aerial parts e.g. Lobelia. 3. Whole undifferentiated plant body or thallus e.g. Ephedra & Ergot.
4 Stem 1. General characters. 2. Shape. 3. Kind. 4. Branching. 5. Surface. 6. Fracture. 7. Structure. 8. Secondary thickening.
5 2- Shape of Stem Cylindrical 1. Cylindrical. stem
2. Angular: with angles & sides; It may be: A. Triangular. B. Quadrangular or square. C. Pentagonal.
3. Ribbed: marked with alternate Ridged ridges & furrows. stem
6 2- Shape of Stem (cont’d.) 2. Winged: marked with wings e.g. Lobelia.
3. Flattened or Collapsed: either normally or by compression or due to shrinkage during drying e.g. Belladonna.
4. Tortuous: Twisted, usually by winding e.g. Convolvulus. Winged stem
7 3- Kind of the Stem
1. Herbaceous: Soft, easily broken, usually green e.g. Mentha.
8 3- Kind of the Stem (cont’d.)
2.Succulent: Thick, Fleshy due to stored water e.g. Euphorbia.
9 3- Kind of the Stem (cont’d.)
3. Woody: In case of shrubs & trees with large amounts of secondary xylem e.g. Eucalyptus. It is usually covered with cork.
10 3- Kind of the Stem (cont’d.)
4. Suffruiticose or shrubby stem: When lower parts are woody & herbaceous in the upper part e.g. Thyme.
11 4- Branching of the Stem 1. Axillary or lateral: a) Monopodial or Racemose or Indefinite Branching; in which the main axis continues to grow, giving off lateral branches that don’t exceed length. b) Sympodial or Cymose or Definite Branching; in which main axis stops growing because apical bud is destroyed or developed into flower or transformed into tendrils. 2. Dichotomous or Apical: in Thallophytes e.g. Chondrus. 12 Dichotomus branching
13 5- Surface of the Stem
1. Smooth or glossy. 2. Rough. 3. Glabrous. 4. Hairy. 5. Spiny. 6. Striated or wrinkled.
14 6- Fracture of the Stem
1. Short: when breaks quickly & straight across smooth fractured surface.
2. Fibrous: when resist during breaking showing fibrous projections protruding from the broken surface.
3. Splintery: when breaking irregularly giving jagged projecting points in the broken surfaces.
4. Flexible: when readily bending & breaks only by twisting.
5. Horny: when it is hard to break.
15 7- Structure of the Stem
T.S. in Monocot stem T.S. in Dicot stem
16 7- Structure of Dicot Stem
1. An epidermis. 2. A cortex. 3. An endodermis. 4. A pericycle. 5. Vascular bundle. Stele 6. Pith.
17 7- Structure of the Stem (cont’d.) B.Vascular Bundle: – Collateral. – Bicollateral. – Concentric {vasocentric or amphivasal).
18 7- Structure of the Stem (cont’d.)
C- Pith: • Parenchyma in the young stems.
• contain starch, calcium oxalate crystals, mucilage or tannins, scattered isolated or grouped sclerenchymatous cells.
• The pith may be solid or hollow.
19 Herbs containing Volatile Oil
Mentha. Thyme.
20 Mentha Thyme
Syn.: Syn.: Herba Menthae Piperitae; Herba Thymi; Common Peppermint. Thyme
Origin: Origin: Dried leaves & flowering tops Dried aerial parts of Thymus of Mentha piperita vulgaris & other Thymus Family Labiatae (Lamiaceae) species, Family Labiatae (Lamiaceae)
21 Mentha
22 Thyme
23 Mentha Thyme
Morphology: Stem: quadrangular, green to Stem: quadrangular, grayish- dark purple, nearly glabrous; brown or purplish & hairy. Herbaceous *suffruiticose Leaves: opposite decussate, Leaves : opposite decussate, petiolate; ovate lanceolate, light *sessile or shortly petiolate. or dark green with purplish tinge, acute apex; sharply serrate margin.
Inflorescence: verticillaster. Inflorescence: verticillaster.
Fruit: nutlet. Fruit: nutlet.
24 Mentha Thyme
Histology: Outline: quadrangular. Quadrangular or circular. Cortex: collenchyma in the Collenchyma is one continuous corners only. layer. Narrow xylem & wide pith. Narrow pith & wide xylem. Less hairy; Glandular hair: Hairy; As in Mentha (Labiaceous & Capitate). Non- glandular hair: (multicellular Non-glandular hair (Unicellular uniserriate).***** conical & bent hair)***. .Diacytic stomata Odor: aromatic .Diacytic stomata. Taste: aromatic followed by a cold Odor: aromatic. sensation Taste: aromatic, spicy.
25 Mentha
Labiaceous hair Diacytic stomata
Capitate hair
Spherical Pollen grain
Non gl. Hair
26 Thyme
Labiaceous hair Diacytic stomata, covered with striated cuticle
Bent hair Spherical Pollen grain
27 Mentha Thyme
Active constituent:
Volatile oil (0.7 to 1.5%), 1% volatile oil (containing which contains up to 78% of phenolic compounds, mainly free menthol & up to 20% of thymol & carvacrol). menthol combined as esters.
Tannins 6 to 12 % tannin (higher). Flavonoids*****. Flavonoid. Saponin.
28 Mentha Thyme Uses & actions: 1-G.I.T: 1- Respiratory tract:****
Spasmolytic. Expectorant (secretolytic,
Carminative. secretomotor, disinfectant & antispasmodic) in cases of Digestive. whooping cough, bronchitis. Anti-emetic. Disinfectant in inhalations. Promotion of liver & gall bladder function (choleretic & 2-G.I.T: cholagogue). Carminative. 2- Externally: Digestive.
Locally anesthetic***. Antispasmodic (Flavonoids)
Antiparasitic. Anthelmintic (vermifuge).
Antipruritic. Antimicrobial. 3- Respiratory tract: The oil should be administered in
Decongestant. the form of enteric-coated capsules.
29 Mentha Thyme
Pharmaceutical preparation: 1. Tooth paste. 1. Cough syrups. 2. mouth washes & gargles. 2. Dental preparations as 3. Soft gelatin capsules. Antiseptic. 4. Aromatherapy****. 3. Anthelmentic. Aromatherapy is now a significant Complementary therapy involving the use of volatile oils to heal or improve well being
30 Pharmaceutical Preparation
31 Mentha Thyme
Chemical Tests: 1. Positive microchemical tests 1. Positive microchemical with Sudan lll. tests with Sudan lll.
2. Special chemical test: 2. Special chemical test: Menthol crystals + few drops Thymol crystals + 1 ml of Conc. H2SO4 + few drops glacial acetic acid + few Of vanillin / H SO → orange- 2 4 drops conc. H2SO4 + 1 drop of yellow color + H O → violet color 2 HNO3 → a deep bluish green color is developed.
32 Herbs Containing Alkaloids
Lobelia Catharanthus.
33 Lobelia • Syn.: Herba Lobeliae Asthma weed, Indian Tobacco, Dukhan Hindi.
• Origin: The dried aerial parts of Lobelia inflata Family Campanulaceae collected towards the end of the flowering stage.
34 Lobelia
Papillosed epidermal Seed coat cells (lignified) Laticiferous vessels in stem & leaf****
Sclerides from pericarp Trichomes
35 Lobelia Active constituents:
• 0.48% alkaloids composed mainly of lobeline & with lesser amounts of lobelanine, lobelanidine & other alkaloids******.
• Lobelic acid, resin, gum and lipids.
• Vitamins A & C.
• Mineral e.g. Manganese.
36 Lobelia Uses: • Lobelia is used widely in cases of spasmodic asthma as it’s anti-spasmodic effect relaxes the bronchial muscles*******.
• It is included in smoking preparations for its expectorant effect & substitution for nicotine*********.
• An injection of lobeline HCl is used in the resuscitation of new-born infants.
• Large doses will cause toxicity and includes symptoms of vomiting & cardiovascular collapse.
37 Catharanthus
• Syn.: Herba Catharanthus Catharanthus, Vinca, Periwinkle.
• Origin: Dried whole plant of Catharanthus roseus (Vinca rosea), Family Apocyanaeae.
38 Catharanthus Active Constituents: • more than 150 alkaloids that have been isolated. • The most important are vinblastine & vincristine (leucocristine) • Vincristine is used more than vinblastine but the plant produces a higher amount of vinblastine. • It is now possible to convert vinblastine into vincristine chemically or microbiologically.
39 Catharanthus Uses of Catharanthus • Alkaloids of Catharanthus possess an oncolytic activity (anti-cancer, anti-neoplastic activity).
• Two of them are currently available in the market as prescription drugs: Vinblastine sulphate for treatment of a wide variety of neoplasma, generalized Hodgkin’s disease & Vincristine sulphate used for the treatment of acute lymphoid leukemia in children.
40 Thallophytes
Fungi e.g. Ergot. Ephedra.
41 Ergot • Syn.: Secale Cornutum, Ergot of Rye.
• Origin: Ergot is the sclerotium of a fungus Clavicips purpurea, Family Claviceptaceae, developed in the ovary of the rye plant, Secale cereale, Family Gramineae.
42 Ergot
Hard structure is known as Sclerotium
43 Ergot The Powder: • Color: greyish, blackish-grey to purplish brown. • Odor: disagreeable. • Taste: disagreeable & oily. It is characterized microscopically by the following: • Numerous small unequal rounded cells with thin highly refractive chitinous walls. • Abundant oily drops and protein matter. • Vascular tissues, trichomes, starch & calcium oxalate are absent*****.
44 Ergot Active Constituents: The official ergot requires containing n.l.t. 0.2 % of total alkaloids, calculated as ergotamine, of which n.l.t.15 % consists of the water soluble alkaloids of Ergot, calculated as ergometrine. • The water soluble alkaloids include one pair: 1-Ergometrine group which consists of: • Ergometrine (ergonovine) & Ergometrinine. • The water insoluble alkaloids are 5 pairs in 2 groups: 1- Ergotamine group which is formed of 2 pairs: • Ergotamine & Ergotaminine. • Ergosine & Ergosinine. 2- Ergotoxine group which is formed of 3 pairs: • Ergocristine & Ergocristinine. • Ergocryptine & Ergocryptinine. • Ergocornine & Ergococorninine.
45 Ergot Active Constituents (cont’d.): • All these 6 pairs of alkaloids are derivatives of lysergic acid.
• Other constituents: histamine, tyramine, other amines and amino acids, acetylcholine.
• Red coloring matter called sclererythrin.
• A yellow body secalonic acid, sterols (fungisterol & ergosterol) and about 3% of fats.
46 Ergot Uses: 1. Ergometrine has stimulant action on plain muscles, especially of the uterus and is used to increase uterine contractions and to reduce postpartum hemorrhage; (oxytocic i.e. quick delivery).
2. Ergotamine group is used to relief migraine alone or with caffeine.
3. Ergotoxine group has antihypertensive action.
4. Ergosterol is used in synthesis of vitamin D.
5. Lysergic acid is used in synthesis of lysergic acid diethylamide (L.S.D.) which has potent psychotomimetic activity
47 Ergot Toxicity: • Ergotism is the consequences caused after the ingestion of ergotized rye bread. • Two forms of epidemic toxicity have been described: – Gangrenous type (St. Antony’s Fire): characterized by agonising pain of the extremities of the body followed by dry gangrene of the peripheral parts.
– Nervous (convulsive) type: giving rise to paroxysmal, epileptic form or convulsions.
48 Ergot
Test for Ergotoxine, Van Urk Test***:
Shake
freshly prepared solution of p- dimethylaminobenzaldehyde (PDMAB) + FeCl in Ergot +Na2CO3+ CHCL3 3 H2SO4Leave for 3 minutes Blue color in the acid layer
49 Ephedra • Syn.: Chinese Ephedra; Chinese Mahuang.
• Origin: Dried young twigs of Ephedra species Family Ephedraceae.
50 Ephedra Constituents: a number of closely related alkaloid which comprises ephedrine, isoephedrine, L-methyl ephedrine, nor-isoephedrine & methyl isoephedrine.
Uses: 1. Sympathomimetic as adrenaline. 2. Relief asthma but having more prolonged action than adrenaline & may be given orally. 3. Decongestant in hay fever & allergic rhinitis. 4. Thermogenic drug thus used in weight loss.
Side effects: 1. Tachycardia. 2. Insomnia & restless.
51