Withania somnifera, known commonly as ashwagandha or winter cherry,[2][3][4] is an evergreen shrub in the Solanaceae or nightshade family that grows in India, the Middle East, and parts of Africa. Several other species in the genus Withania are morphologically similar.[3]
The plant, particularly its root powder, has been used for centuries in traditional Indian medicine. Although used in herbalism and sold as a dietary supplement, there is insufficient scientific evidence that it is safe or effective for treating any health condition or disease.[3][4]
Description
This species is a short, tender shrub growing 35–75 cm (14–30 in) tall. Tomentose branches extend radially from a central stem. Leaves are dull green, elliptic, usually up to 10–12 cm (3.9–4.7 in) long. The flowers are small, green and bell-shaped. The ripe fruit is orange-red.[3]
Etymology
The Latin species name somnifera means "sleep-inducing".[5] The name "ashwagandha" is a combination of the Sanskrit words 'ashva', meaning horse, and 'gandha', meaning smell, reflecting that the root has a strong horse-like odor.[3]
Cultivation
Withania somnifera is cultivated in many of the drier regions of India. It is also found in Nepal, Sri Lanka, China,[6] and Yemen.[7] It prefers dry stony soil with sun to partial shade. To propagate it can be grown from seed in the early spring, or from greenwood cuttings in the later spring.[8]
Diseases and pests
Withania 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. A decline in the concentration of its secondary metabolites occurs by leaf spot disease.[9] A treehopper feeds on the apical portions of the stem, making them rough and woody in appearance and brown in colour.[citation needed]
The carmine red spider mite (Tetranychus urticae) is the most prevalent pest of the plant in India.[10] In recent years, this plant has been serving as a new reservoir host for an invasive mealybug species Phenacoccus solenopsis.[11]
Phytochemistry
The main phytochemical constituents are withanolides – which are triterpene lactones – withaferin A, alkaloids, steroidal lactones, tropine, and cuscohygrine.[3] Some 40 withanolides, 12 alkaloids, and numerous sitoindosides have been isolated.[3] Withanolides are structurally similar to the ginsenosides of Panax ginseng, leading to a common name for W. somnifera, "Indian ginseng".[3]
Adverse effects
W. somnifera may cause adverse effects if taken alone or together with prescription drugs.[3][4][12] Side effects may include diarrhea, headache, sedation, or nausea, and the product should not be used during pregnancy or breastfeeding.[4][12]
Gallery
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Fruits
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Druggist's jar containing dried roots of Withania somnifera
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Dried graded roots of Withania somnifera
