Withania somnifera, known commonly as ashwagandha[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.[5] Ashwagandha
supplements, typically containing root or leaf powder or
extracts, are commonly sold.[4] Its use in
herbal medicine and dietary supplements notwithstanding, there is insufficient scientific evidence that W. somnifera is safe or effective for treating any health condition or disease.[3][4]
Description
This species is a short 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'.[6] 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
W. somnifera is cultivated in many of the drier regions of
India. It is also found in
Nepal,
Sri Lanka,
China, and
Yemen.[7][8] 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.[9]
A
treehopper (Oxyrachis tarandus) feeds on the
apical portions of the stem, making them rough and woody in appearance and brown in colour.[12]
The
carmine red spider mite (Tetranychus urticae) is the most prevalent pest of the plant in India.[13] In recent years, this plant has been serving as a new reservoir host for an invasive
mealybug species Phenacoccus solenopsis.[14]
Limited, low-quality clinical studies have found that supplementation with various ashwagandha
extracts may decrease perceived
stress and
anxiety, and improve sleep.[3][4][16] Because the studies used different extract preparations, durations of use, doses, and types of subjects, it remains undetermined how ashwagandha may have effects in people, as of 2023.[3][4][16]
Adverse effects
W. somnifera may cause
adverse effects if taken alone or together with
prescription drugs.[3][4][17] A review of 30 clinical trials found that use of W. somnifera may cause problems with sleep, blurred vision, stomach pain, dry mouth, vertigo, among others.[18] The most common side effects include
diarrhea, headache,
sedation, or
nausea, and the product should not be used during pregnancy or breastfeeding.[4][17] Ashwagandha may increase
testosterone levels which could adversely interact with cancer medications.[3][17][19]
Gallery
Fruits
Druggist's jar containing dried roots of Withania somnifera
^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.
PMID23142795.
^Hugh Scott & Kenneth Mason, Western Arabia and the Red Sea, Naval Intelligence Division: London 1946, p. 597
ISBN0-7103-1034-X.
^Sharma, A; Pati, P.K. (2011). "First report of Withania somnifera (L.) Dunal, as a New Host of Cowbug (Oxyrachis tarandus, Fab.) in plains of Punjab, Northern India". World Applied Sci. J. 14 (9): 1344–1346.
^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.
S2CID85645762.
^
abc"Ashwagandha". Memorial Sloan Kettering Cancer Center. 21 March 2023. Retrieved 4 April 2024.
^Tandon N, Yadav SS (June 2020). "Safety and clinical effectiveness of Withania somnifera (Linn.) dunal root in human ailments". Journal of Ethnopharmacology. 255: 112768.
doi:
10.1016/j.jep.2020.112768.
PMID32201301.