Withania somnifera, known commonly as ashwagandha or winter cherry, 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.
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.
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.
The Latin species name somnifera means "sleep-inducing". 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.
Withania somnifera is cultivated in many of the drier regions of India. It is also found in Nepal, Sri Lanka, China, and Yemen. 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.
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. A treehopper feeds on the apical 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. In recent years, this plant has been serving as a new reservoir host for an invasive mealybug species Phenacoccus solenopsis.
The main phytochemical constituents are withanolides – which are triterpene lactones – withaferin A, alkaloids, steroidal lactones, tropine, and cuscohygrine. Some 40 withanolides, 12 alkaloids, and numerous sitoindosides have been isolated. Withanolides are structurally similar to the ginsenosides of Panax ginseng, leading to a common name for W. somnifera, "Indian ginseng".
W. somnifera may cause adverse effects if taken alone or together with prescription drugs. Side effects may include diarrhea, headache, sedation, or nausea, and the product should not be used during pregnancy or breastfeeding.
- "Withania somnifera (L.) Dunal". Tropicos. Missouri Botanical Garden. Retrieved 25 Feb 2012.
- "Withania somnifera". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA). Retrieved 2011-10-29.
- "Ashwagandha". Drugs.com. 2 November 2020. Retrieved 2 February 2021.
- "Ashwagandha". MedlinePlus, US National Library of Medicine. 28 August 2020. Retrieved 21 September 2020.
- Stearn, W. T. (1995). Botanical Latin: History, Grammar, Syntax, Terminology and Vocabulary (4th ed.). Timber Press. ISBN 978-0-88192-321-6.
- Pandit, S.; Chang, K.-W.; Jeon, J.-G. (February 2013). "Effects of Withania somnifera on the growth and virulence properties of Streptococcus mutans and Streptococcus sobrinus at sub-MIC levels". Anaerobe. 19: 1–8. doi:10.1016/j.anaerobe.2012.10.007. PMID 23142795.
- Hugh Scott & Kenneth Mason, Western Arabia and the Red Sea, Naval Intelligence Division: London 1946, p. 597 ISBN 0-7103-1034-X.
- Deni., Bown (1995). Encyclopedia of herbs & their uses. Montréal: RD Press. ISBN 0888503342. OCLC 32547547.
- Pati, P. K.; Sharma, M.; Salar, R. K.; Sharma, A.; Gupta, A. P.; Singh, B. (2009). "Studies on leaf spot disease of Withania somnifera and its impact on secondary metabolites". Indian Journal of Microbiology. 48 (4): 432–437. doi:10.1007/s12088-008-0053-y. PMC 3476785. PMID 23100743.
- Sharma, A.; Pati, P. K. (2012). "First record of the carmine spider mite, Tetranychus urticae, infesting Withania somnifera in India". Journal of Insect Science. 12 (50): 1–4. doi:10.1673/031.012.5001. PMC 3476950. PMID 22970740.
- Sharma, A.; Pati, P. K. (2013). "First record of Ashwagandha as a new host to the invasive mealybug (Phenacoccus solenopsis Tinsley) in India". Entomological News. 123 (1): 59–62. doi:10.3157/021.123.0114. S2CID 85645762.
- "Ashwagandha". New York City: Memorial Sloan Kettering Cancer Center. 13 April 2018. Retrieved 26 May 2018.
- Media related to Withania somnifera at Wikimedia Commons