Botanical origin : Withania somnifera (L.) Dunal
English name : Indian ginseng, Winter cherry
Family : Solanaceae
Synonyms : Physalis somnifera
Common Indian names :
Hindi : Asgandh
Sanskrit : Ashvagandha, Balada, Gandhpatri, Kamrupini, Vajini
Gujarati : Asam, Asoda, Ghodasoda
Punjabi : Asgand
Telugu : Asvagandhi, Pennereu, Vajigandha
Tamil : Asuragandhi, Amukkira
Bengali : Ashvagandh
Urdu : Asgandanagaori
Marathi : Asgundh, Kanchuki, Askandha
Canarese : Amangura, Hirimaddina-gadde, Sogada-bery
Kingdom : Plantae
Division : Angiosperma
Class : Dicotyledoneae
Order : Tubiflorae
Family : Solanaceae
Genus : Withania
Species : W. somnifera
Parts used : Roots, stems, leaves, fruits and seeds.
The genus Withania is reported to have 23 species out of which, Withania somnifera (L.) Dunal. is ofhigh medicinal value. Withania somniferais cosmopolitan and grows throughout the drier parts and subtropical regions. Thewild growth of this species has also been reported from India, Pakistan,Afghanistan, Philistine, Egypt,Jordan, Morocco, Sri Lanka,Spain, CanaryIsland, Eastern Africa, Congo, Madagascarand South Africa.These areas represent wide variations of soil, rainfall, temperature andaltitude (Kokate et al., 1996) (Fig.-4.1).
India is situated between 8o 4”to 37o 6” N latitude and 68o 7” to 97o 25” Elongitude. The total land area of India is approximately 329mha, outof which 150mha of land area is uncultivable and around 90mha is characterizedas wasteland (Hegde, 1985). Withaniasomnifera is widely distributed in the warmer parts and tropical areas of India. InIndia, Ashwagandha is widely distributed in north-western region, Maharashtra,Gujarat, Rajasthan, Madhya Pradesh, Urrisa, Uttar Pradesh, Punjab plainsextending to the mountain regions of Punjab, Himachal Pradesh and Jammu,ascending to a height of 1500 m. but not common in Kerala (Kokate et al.,1996) (Fig.-4.2).
In Rajasthan, Withania somnifera is widely distributed in arid, semi-arid regionsDholpur, Bharatppur, Jaipur, Alwar, Dausa, Jodhpur, Ajmer, Udaipur, Kota, etc. Withania somnifera is distributed mainlyin Nagaur as Nagauri ashwagandha (Fig.-4.3).
Plant: Theplant is an erect, perennial, much branched undershrub growing to1-3m in height
Stem: It is terate, branched, cylindrical, solid, clothed with mealy, stellate-hoarytomentun, at length somewhat glabrous
Root: Roots straight, unbranched, thickness varying with age, roots bear fibre like secondary roots, outer surface buff to gray yellow with longitudinal wrinkles;crown consists of 2-6 remains of stem base; stem bases variously thickened;nodes prominent only on the side from where petiole arises, cylindrical, greenwith longitudinal wrinkles; fracture, short and uneven; odour, characteristic;bitter and acrid. The roots when dry are cylindrical, gradually tapering down with a brownish white surface and pure white inside when broken
Leaves: Leaves are cauline and ramal, simple, exstipulate, petiolate, ovate, acute, entire,and up to 10 cm long. Petioles up to 1.25 cm long. The leaves on vegetative shoots are alternate and large while those on floral branches are opposite,rounded or some what produced at base, pubescent on lower surface and glabrous on upper surface unicostate, reticulate venation. Arranged in pairs of one large and one small leaf and arranged some what laterally, having in their axila cymose cluster of 5-25 inconspicuous pale green flowers .
Inflorescence: It is solitary, axillary
Flowers: Flowers are ebracteate, pedicellate, complete, hermaphrodite, pentamerous,actinomorphic and hypogynous, gamosepalous, 4-6 mm in diameter, lucid-yellow or greenish.
Calyx : Sepals are five, fused, tubular,persistent, green, hairy.
Corolla : Petals are five, united, tubular, gamopetalous, lobes spreading or recurved, acute,pubescent and greenish yellow. Aestivation is valvate or imbricate.
Androecium : Stamens are five, attached near the base of the corolla, epipetalous, anthers oblong, dehiscing longitudinally, introrse, dithecous, filament deeply inserted in corolla tube ,linear slender
Gynoecium : It is bicarpellary, syncarpous, composedof minute swollen ovary, ovary superior, placed obliquely, placentation axile,with many ovules in each locule, style simple, stigma shortly bifid
Flowering time : Winter
Fruits : Fruitis a berry enclosed in the green persistent calyx, 5 mm in diameter, smooth,more or less globose, green when unripe, orange-red coloured in ripening stage
Seeds : Bean shaped, endospermic, yellow andorange-red coloured, some what scurfy. Fruit contains numerous small Capsicum like seeds .
ANATOMY OF DIFFERENT PARTS OF WITHANIA SOMNIFERA
For histology, fresh roots were taken from two-years-old plant of W. somnifera.Fresh hand cut sections were stained following Johansen (1940) and mounted with glycerin and examined under light microscope (Nikon).
The medicinal drug consists of the dried roots of W.somnifera which occur in small pieces, 10.0-17.5 cm long and 6-12 mm indiameter. The bases of stem are also present. The pieces are dark brown with acreamy interior. They are straight, unbranched and conical. The main roots bearfibre like secondary roots. Their outer surface is buff to gray yellow withlongitudinal wrinkles. The stem bases are variously thickened, cylindrical andgreen and have longitudinal wrinkles. The young tuberous roots and older rootshave distinct macroscopic and microscopic characters (PLATE-4.3-B).
The powdered drug is grayish with pungent odour and acid taste. It is characterizedby the presence of a large number of starch grains, cork cells, cortical and xylem parenchyma, tracheids, vessels and wood fibres
The water insoluble extract was also found to contain a number of substances which had been isolated from the root of the plants. Majumdar and Guha (1933) investigated the Bengal variety of plants and demonstrated the presence of three alkaloids. Two new and seven known withanolides along with β-sitosterol, stigmasterol, β-sitosterol glucoside, stigmasterol glucoside, α + β glucose were isolated from the roots of Withania somnifera. Among the known compounds, viscosa lactone B, stigmasterol, stigmasterol glucoside and α+ β glucose are being reported from the roots of W. somnifera for the first time. One of the new compounds contained the rare 16β-acetoxy-17(20)-ene the other contained unusual6α-hydroxy-5,7α-epoxy functional groups in the withasteroid skeleton. The structures were elucidated by spectroscopic methods and chemical transformations (Mishra et al.,2008).
Uses and pharmacological actionof Ashwagandha
Sincethe time of Acarya Caraka, ashwagandha has been used for the cure of various diseases. In Indian system of medicines, it is regarded as very good sex stimulant and is also used mixed with other drugs for the cure of rheumatism,gout, skin diseases, nervous disorders, insanity, hypertension, ulcers,swellings, dyspepsia, lumber pains, abortion, opthalmia,relieving hand and limb tremors, aphrodisiac, etc. The leaves are supposed to reduce pus formation, inflammation and to promote healing processes. Fruits are also considered as diuretic (Prasad et al., 1959 and Shash et al.,1959). W. somnifera or its major active principles suppress cyclophosphamide toxicity (Davis and Kuttan, 1998).
W. somnifera had been found to contain no mydriatic alkaloid. Withanolides serve as important hormone precursors which the body is then able, as needed, to convert in to human physiological hormones. If there is an excess of a certain hormone,the plant based hormone precursors occupy the so-called hormone receptor sites,without converting to human hormones, to block absorption. In this way, ashwagandha,like other adapogenic tonic herbs is amphoteric and can serve to regulatei mportant physiological processes increasing or decreasing as needed.
Weiner and Weiner (1994) concluded that several diseases induced by stress are cured by root rasayans and this rasayan isreported to promote health and logevity by augmenting difference against diseases arresting process revitalizing the body in debilitated conditions,increasing the capability of the individual to resist adverse environmental factors and by creating a sense of mental well being. Kuboyama et al. (2002) reported that methanol extract of ashwagandha (roots of Dunal) induced dendrite extension in a human neuroblastoma cell line. Zhao et al. (2002)reported the effect of withanolide derivatives on neurite outgrowth.
Researchers from Banaras HinduUniversity in Varanasi, India,have discovered that some of the chemicals within ashwagandha are powerful antioxidants (Bhattacharya, 1998). They tested these compounds for their effects on rat brain and found an increase in the levels of three naturalantioxidants, superoxide dismutase, catalase and glutathione peroxidase. They say, “these findings are constant with the therapeutic use of W. somnifera as an Ayurvedic rasayana(health promoter)”. The antioxidant effect of active principles of W. somnifera may explain, at least in part, the reported anti-stress, cognition facilitating, anti-inflammatory and anti ageing effects produced by them in experimental animals and in clinical situations (Kurup, 1956; Panda and Kar, 1997 and Dhuley, 1998). Similarly the immunomodulatory effect (Ghosal,1999) and inhibition of cognitive deficits in animal models of Alzheimer’sdisease (Bhattacharya et al., 1995) reduced by W. somnifera glycowithanolides(WSG) may also be related to possible antioxidant effect. Bhattacharya et al. (1997) reported effect of theactive principles of W. somniferaconsisting of sitoindoside VII-X and withaferin-A and antioxidant effect in ratbrain frontal cortex and striatum. A W.somnifera containing Ayuvedic herbal formulation was found to attenuatestreptozotocin-induced hyper glycaemia in rats, concomitant with augmentedoxidative free radical scavenging activity in the pancreas (Bhattacharya et al., 1997a). Recent studies(Bhattacharya et al., 2000) haveshown that chronic unpredictable footshock stress in rats, reduces glucosetolerance, immunosuppression, behavioural cognitive and male sexual dysfunctionwhich were attenuated by W. somnifera glycowithanolides (WSG) was due to its anti-oxidative stress action.
Ashwagandha is used in India to treatmental deficits in geriatric patients, including amnesia. Researchers from the University of Leipzing in Germany,studied the influence of ashwagandha on neurotransmitters (Bhattacharya, 1998).After injecting some of the chemicals of ashwagandha in rats, he later examined slices of their brain and found an increase in acetylcholine receptor activity.The researchers say, “the drug increases in acetylcholine receptor capacity,might partly explain the conditions enhancing and memory-improving effects ofextracts from Withania somnifera observed in animals and humans.” A study done in 1991 at the department ofpharmacology, University of Texas, health sciencecentre, indicated that extracts of ashwagandha had GABA-like activity. This may account for this herb’s antianxiety effects.
Action and uses in Ayurveda and Siddha
Tikta,kashaya rasam ushna veeryam, katu vipakam, kapha vata haram.
Indications : Vranam, visham, aphrodisiac, strength giving, complexion improved, inkasam, swasam, soola, pandu, white leprosy, pruritis, karappan, fatigue, srerilityof women, spermatorrhoea.
Action and uses in Unani
Cough, asthma, uterine diseases,expels balgham and sauda, aphrodisiac, puerperal tonic. Here are someapplications of this herb.
Mental problem improved
This is perhaps one of the most promising applications of this herb. In a reported study, this herb was given to 30 mental patients suffering from anxiety neurosis in doses of 40 ml/day for one month. At the end of the month, most of the anxiety disorders, panicattacks and similar mood phobias, had disappeared. In trial by American psychiatrists, this herb had been found useful for the treatment of manic depression, alcoholic paranoia and schizophrenia.