Limnophila (Scrophulariaceae): Chemical and Pharmaceutical Aspects - an Update
Total Page:16
File Type:pdf, Size:1020Kb
Send Orders for Reprints to [email protected] The Open Natural Products Journal, 2014, 7, 1-14 1 Open Access Limnophila (Scrophulariaceae): Chemical and Pharmaceutical Aspects - An Update Goutam Brahmachari* Laboratory of Natural Products & Organic Synthesis, Department of Chemistry, Visva-Bharati (a Central University), Santiniketan-731 235, West Bengal, India Abstract: The present resumé covers an up-to-date literature on Limnophila species. The botanical classification, ethno- pharmacology, and chemical constituents of Limnophila plants, as well as the biological activities and pharmacological applications of both distinct phytochemicals and medicinally active plant materials (formulations, extracts, etc.) are dis- cussed in detail. Keywords: Biological activities, Botany, Chemical constituents, Ethno-pharmacology, Limnophila species, Pharmacological applications, Taxonomical classification. INTRODUCTION feet long. The emergent stems are usually 2-15 cm above the surface of the water. Single white, pink, purple or blue to Limnophila (family: Scrophulariaceae) [1-5] is originated lavender flowers, sometimes with conspicuous spots, occa- from a Latin word that means pond-loving indicating its ex- sionally occur on the emerged portion of the stem. The flow- istence in aquatic environments. It is commonly known as ers are stalkless and borne in the leaf axis, and are axillary ‘Ambulia’ (Asian marshweed). It is a perennial herb from and solitary or in axillary or terminal spikes or racemes, Southeast Asia, tropical to subtropical Africa, Australia, and sessile or pedicellate. The lower portion (sepals) has five, Pacific Islands; also finds adventive distribution in North green, hairy lobes, each 4-5 mm long. The upper portion is America. Limnophila plants are widely distributed through- purple and composed of five fused petals forming a tube out India, and occupy a significant position in traditional with two lips — adaxial lip (dorsal) is 2-lobed, while abaxial systems of medicine. A number of plant species are in use as lip (ventral) is 3-lobed. The lips have distinct purple lines on folk medicines in the treatment of various ailments. A num- the undersides. The fruit is capsule containing up to 150 ber of works on chemical and pharmacological aspects of seeds. genus Limnophila have already been done. Here an attempt, for the first time as per our record, has been made to compile Limnophila reproduces through fragmentation of the all these works that are in scattered in literatures. Although stem or by seeds. In post-rainy session the fruits of Limno- some works on the genus have been done, a major portion phila are mature, and the mats break loose from the hydro- remains unexplored. This review is designed in such a fash- soil — as the floating-mats move, they spread out the seeds ion so that it would surely boost the ongoing research in this throughout a wider area. direction. That’s why an all round and up-to-date resumé — covering its botany to ethnobotany, biological and pharma- TAXONOMICAL BACKGROUND cological studies as well as phytochemicals as reported so far The taxonomical classification [8, 9] of Limnophila plants — on this important plant genus has been compiled. are shown below: BOTANICAL ASPECTS Kingdom Plantae Limnophila [6, 7] is an aquatic, or nearly aquatic, peren- nial herb found as submersed, emergent, and amphibious Subkingdom Tracheobionta stem plant. Its natural habitats are rivers, lakes, ponds as well Division Magnoliophyta as marshy lands. The submerged stems are smooth and have feathery leaves with 30 mm long encircling about the stems. Class Magnoliopsida These differ from the emergent stems, which are covered Subclass Asteridae with flat shiny hair and have leaves, generally lance-shaped, up to 3 cm long with toothed margins. Stems may be up to 12 Order Scrophulariales Family Scrophulariaceae *Address correspondence to this author at the Laboratory of Natural Prod- Genus Limnophila R. Brown ucts & Organic Synthesis, Department of Chemistry, Visva-Bharati (a Cen- tral University), Santiniketan-731 235, West Bengal, India; Tel: +91-3463-261526; Fax: +91-3463-261526; About 40 species [10] of the genus Limnophila are E-mails: [email protected] and [email protected] known; some common species are cited here: 1874-8481/14 2014 Bentham Open 2 The Open Natural Products Journal, 2014, Volume 7 Goutam Brahmachari L. aromatica (Lamarck) Merrill. L. laotica Bonati considered to be carminative and antiseptic. A liniment (Syn. L. aromaticoides Yang & Yen; L. laxa Bentham prepared from the plant is used in elephantiasis. The L. gratissima Blum) L. micrantha (Benth.) Bentham juice of the plant is rubbed over the body in pestilent L. australis Wannan & Waterh. L. parviflora Yamazaki fevers. It is given internally in dysentery combined with L. balsamea (Benth.) Benth. L. poilanei Yamazaki ginger, cumin and other aromatics [12-14]. (Syn. L. thorelii Bonati) L. polyantha Kurz ex Hook.f. (iv) L. conferta: The plant has been employed to treat vari- L. borealis Y. Z. Zhao & Maf. (Syn. L. polyantha Yamazaki) ous types of skin diseases and conditions of inflamma- L. brownii Wannan L. repens (Bentham) Bentham tion in the indigenous system of medicine [14, 16]. L. chinensis (Osbeck) Merill (Syn. L. conferta Bentham; (Syn. L. chevalieri Bonati; L. hirsuta L. dubia Bonati; L. sessilis CHEMICAL CONSTITUENTS OF LIMNOPHILA (Heyne ex Benth.) Benth. (Bentham) Fischer L. connata (Buchanan-Hamilton ex D. L. rugosa (Roth) Merill The phytochemical investigation of the genus Limno- Don) (Syn. L. roxburghii G. Don) phila, as carried out so far, has afforded a good number of Handel-Mazzetti L. sessiliflora (Vahl) Blume compounds, previously known from other natural sources or L. erecta Bentham L. siamensis Yamazaki isolated as new phytochemicals. These compounds are of L. fragrans Seem L. taoyuanensis Yang & Yen varying structural skeletons and are classified into flavonoids L. geoffrayi Bonati L. verticillata Yamazaki (1-23; Fig. 1) (Table 1), terpenoids (24-60; Fig. 2) (Table 2), L. hayatae Yamazaki L. villifera Miq. and miscellaneous (61-87; Fig. 3) (Table 3). L. heterophylla (Linnaeus) Druce (Syn. L. X ludoviciana Thieret L. reflexa Bentham) L. dasyantha Skan BIOLOGICAL/PHARMACOLOGICAL ACTIVITIES L. indica (Linnaeus) Druce (Syn. L. L. glabra (Benj.) Kerr OF CRUDE PLANT MATERIALS AS WELL AS OF gratioloides R. Brown; L. racemosa L. hottonoides Druce CHEMICAL CONSTITUENTS Bentham; L. aquatica Roxburgh) L. gigantean A good number of biological/pharmacological works TRADITIONAL USES with different parts of Limnophila plants as crude extracts and also of pure chemical constituents isolated from these Limnophila plants are extensively used in the indigenous plant species have been reported so far. This section is an system of medicine, and are found to be useful and effective. attempt to sum up all these findings. Traditional uses of only a few of these significant plant spe- cies finding useful applications in the treatment of various Antimicrobial Activity ailments are mentioned here. The medicinal uses of these plant species are being cited on the basis of extensive litera- Limnophila plants are reported to exhibit significant an- ture survey. timicrobial activity. L. racemosa and L. indica extracts were (i) L. aromatica (Syn. L. gratissima): The plant is used as found to inhibit the growth of Xanthomonas campestris and a spinach, eaten raw or steamed. It is sour, slight bitter X. malvacearum in vitro [50]. Mishra et al. [51] also studied refrigerant emollient antiseptic, galactagogue, aperient, the antimicrobial activity of the same plant extracts against a appetizer, digestive, carminative, anthelmintic, anti- number of bacterial species and obtained a convincing result inflammatory, diuretic and febrifuge. It is useful in viti- (Table 4) on the basis of which the workers pointed out that ated conditions of pitta, foul ulcers, agalactia, galactic both the extracts of L. racemosa and L. indica bear certain impurities, anorexia, dyspepsia, helminthiasis, constipa- antimicrobial components. tion, inflammations and strangury. The juice of the Antibacterial efficacy of the essential oil of L. conferta plant is used as a cooling medicine in fever and was also established by Reddy et al. [33] against the Gram- pharyngitis. It is given to nursing women, when the positive bacteria, Staphylococcus aureus and Bacillus sub- milk is sour. The plant emits turpentine-like odour and tilis, and two Gram-negative bacteria, Escherichia coli and yields an essential oil [11-13]. Pseudomonas aeruginosa. The significant antimicrobial ac- (ii) L. rugosa (Syn. L. roxburghii): The plant shows nu- tivity of the essential oil of L. conferta, comparable with that merous medicinal applications in the traditional system. of chloramphenicol used as standard and ethylene glycol as The juice of the plant is rubbed over the body in pesti- control solvent justifies the use of this plant in the indige- lent fever. It is applied on elephantiasis with coconut nous system of medicine in controlling some infections. The oil. It is administered in diarrhoea, dysentery and dys- oil was not found to be toxic at a dose level of 1.6 mL/Kg pepsia. It is used as carminative and tonic. The essential orally. oil is used as flavouring agent of food and perfuming of hair oils. The essential oil of this plant also exhibits Reddy et al. [33] reported that the essential oil of L. significant anti-bacterial and anti-fungal activities. The gratissima (Syn. L. aromatica)