| Withania somnifera | |
|---|---|
| Ashvagandha plant at Talkatora garden, Delhi | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Solanales |
| Family: | Solanaceae |
| Genus: | Withania |
| Species: | W. somnifera |
| Binomial name | |
| Withania somnifera (L.) Dunal[1] |
|
| Synonyms | |
|
Physalis somnifera |
|
Withania somnifera, also known as Ashwagandha, Indian ginseng, Winter cherry, Ajagandha, Kanaje Hindi, Amukkara (Tamil), Samm Al Ferakh, is a plant in the Solanaceae or nightshade family. Withania coagulans (Dunal) (Paneer dodi, Ashutosh booti) is a related species.
It is used as a herb in Ayurvedic medicine.
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It grows as a short shrub (35–75 cm) with a central stem from which branch extend radially in a star pattern (stellate) and covered with a dense matte of wooly hairs (tomentose). The flowers are small and green, while the ripe fruit is orange-red and has milk-coagulating properties. The plant also has long brown tuberous roots that are used for medicinal purposes.[2]
There are two sub-species of Withania somnifera. W. somnifera Kaul was named after the Indian botanist Kailas Nath Kaul, who was the pioneer of modern scientific research on the plant.[3] The other is W. somnifera Dunal.
There are 23 species of the Withania genus that occur in the dry parts of India, North Africa, Middle East, and the Mediterranean.[2]
The main active constituents are alkaloids and steroidal lactones. These include tropine and cuscohygrine. The leaves contain the steroidal lactones, withanolides, notably withaferin A, which was the first withanolide to be isolated, and was isolated from W. somnifera.
Withaferin A inhibits notch-1 signaling and downregulates prosurvival pathways, such as Akt/NF-κB/Bcl-2, in three colon cancer cell lines (HCT-116, SW-480, and SW-620).[4] Recent research in mice suggests that withaferin A may have anti-metastatic activity.[5]
Ashwagandha in Sanskrit means "horse's smell", probably originating from the odor of its root which resembles that of a sweaty horse.
The species name somnifera means "sleep-inducing" in Latin.
W. somnifera is cultivated in many of the drier regions of India such as Mandsaur District of Madhya Pradesh, Punjab, Sindh, and Rajasthan.[2] It is also found in Nepal.
W. somnifera is grown as late rainy season (kharif) crop. Semi-tropical areas receiving 500 to 750 mm rainfall are suitable for its cultivation as a rainfed crop. If one or two winter rains are received, the root development improves.
The crop requires a relatively dry season during its growing period. It can tolerate a temperature range of 20°C to 38°C and as low a temperature as 10°C. The plant grows from sea level to an altitude of 1500 meters.
W. somnifera is prone to several pests and diseases. Leaf spot disease caused by Alternaria alternata is the most prevalent disease, which is most severe in the plains of Punjab, Haryana, and Himachal Pradesh. Biodeterioration of its pharmaceutically active components during leaf spot disease has been reported.[6] Oxyrachis tarandus (a Treehopper/cowbug species) feeds on the apical portions of the stem, making them rough and woody in appearance and brown in colour. The apical leaves are shed off and the plant gradually dies away.[7]
The berries can be used as a substitute for rennet, to coagulate milk in cheese making.[2]
In Ayurveda, the roots of W. somnifera are used to prepare the herbal remedy Ashwagandha. Ashwaganda has been traditionally used to treat various symptoms and conditions, although there are few scientific studies of the health benefits of the compound.[2][8][9][10][11][12]
In Ayurveda, the berries and leaves are locally applied to tumors and tubercular glands, carbuncles and ulcers.[2]
In at least two published clinical trials of W. somnifera, the side effects were not significantly different from those experienced by placebo treated individuals.[11] [13] There has been one case report that Withania somnifera stimulated the thyroid and lead to thyrotoxicosis in the patient.[14]