Withania somnifera, known commonly as ashwagandha,[ Several other species in the genus Withania are morphologically similar.][ Common names include Indian ginseng and winter cherry.]
W. somnifera is a short shrub 35–75 cm tall with Trichome branches, dull green Ellipse leaves up to 10–12 cm long, small green bell-shaped flowers, and orange-red ripe fruit. The Latin species name somnifera means “Hypnotic,” while the name ashwagandha combines the Sanskrit words for “horse” and “smell,” referring to the root’s strong horse-like odor. It is cultivated mainly in dry regions of India and nearby countries like Nepal, Sri Lanka, China, and Yemen, preferring dry, stony soil with sun to partial shade, and is propagated from seeds in early spring or greenwood cuttings later. It is affected by various pests and diseases in India, which can damage plant health and reduce its secondary metabolite content.
The plant, particularly its root powder, has been used for centuries in Ayurveda.
W. somnifera is generally well tolerated for up to about 3 months with mostly mild Side effect[ It has been linked to rare cases of liver injury, particularly in people with preexisting liver conditions.]
Description
This species is a short shrub growing tall. Tomentose branches extend radially from a central stem. Leaves are dull green, elliptic, and usually up to long. The flowers are small, green, and bell-shaped. The ripe fruit is orange-red.[
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Etymology
The Latin species name somnifera means "sleep-inducing".[
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Cultivation
W. somnifera is cultivated in many of the drier regions of India. It is also found in Nepal, Sri Lanka, China, and Yemen.[Hugh Scott & Kenneth Mason, Western Arabia and the Red Sea, Naval Intelligence Division: London 1946, p. 597 .] It prefers dry, stony soil with sun to partial shade. It can be propagated from seeds in the early spring or from greenwood cuttings in the later spring.
Diseases and pests
W. somnifera is prone to several pests and diseases. Leaf-spot disease caused by Alternaria alternata is the most prevalent disease, which occurs in a severe form in Punjab, Haryana, and Himachal Pradesh. Leaf-spot disease reduces the concentration of its secondary metabolites.
A treehopper ( Oxyrachis tarandus) feeds on the apical meristem portions of the stem, making them rough and woody in appearance and brown in colour.
The carmine red spider mite ( Tetranychus urticae) is the most prevalent pest of the plant in India.
Phytochemistry
The main phytochemistry constituents of W. somnifera are , a group of triterpene that include withaferin A, , , tropine, and cuscohygrine.[ Forty withanolides, twelve alkaloids, and various sitoindosides have been isolated from this plant species.][
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Traditional medicine and dietary supplements
The plant, particularly its root powder, has been used for centuries in Ayurveda.
Stress and anxiety
At oral doses of 300 to 600 mg per day over a three month period, ashwagandha root extract may be useful in treating generalized anxiety disorder, although the evidence for efficacy is tentative and the treatment may cause nausea and diarrhea.
Sleep
There is limited evidence that W. somnifera extract, especially at higher doses and over longer durations, may modestly improve sleep quality and related outcomes, with more noticeable effects in people with insomnia.[ A 2021 review concluded that W. somnifera extract modestly improves sleep quality and quantity in adults, especially those with insomnia, and may reduce anxiety and enhance alertness.]
Adverse effects
W. somnifera may cause if taken alone or together with prescription drugs.[
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W. somnifera can cause hepatotoxicity, and its use as a supplement has been linked to herb-induced liver injury,
Use of W. somnifera is not recommended during pregnancy or in people with hormone-sensitive prostate cancer.
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