Standardized Common Name: Ashwagandha

Other Common Name: Winter Cherry

Family: Solanaceae

Taxonomy: Withania includes about a dozen species, broadly distributed but restricted to certain subtropical regions. Withania somnifera is one of two species native to India. It grows wild in the Mediterranean, Africa, and Australia (where it is naturalized), and is widely cultivated. The basionym is Physalis somnifera L.; several synonyms exist. One of these is W. obtusifolia Tackh., referring to certain distinctive populations in Egypt and Saudi Arabia that may be distinguished as W. somnifera subsp. obtusifolia (Tackh.) Abedin, Al-Yahya, Chaudhary & Mossa. The name Withania ashwagandha Kaul has been used for cultivated material, but this name was not validly published and there is little justification for treating cultivated plants as a separate species. There is considerable variation within the species, in both wild and cultivated material.

Description: Shrub, 0.3–1.5(–2.1) m tall, only the lower part becoming woody. Stems sparsely to frequently branching, densely pubescent with branching hairs. Leaves alternate beneath, often opposite above, broadly ovate to ovate-lanceolate or elliptic, (2–)4–10(–16) cm long, thin or somewhat leathery, usually densely pubescent with branching hairs especially on lower surface and when young, sometimes nearly glabrous in subsp. obtusifolia; base cuneate to attenuate, oblique or nearly truncate in subsp. obtusifolia; apex acute to obtuse; margins undulate to entire; venation pinnate. Inflorescences of (1–)4–6(–16) flowers, clustered in leaf axils. Pedicels usually short, 4–8 mm long in subsp. obtusifolia; calyx (2–)4–5 mm long, pubescent, basally fused, with 5 acute lobes, the tube inflating in fruit; corolla (2–)5–8 mm long, yellowish green, pubescent, the lower portion fused and campanulate, 5-lobed, the lobes linear to ovate-triangular and sometimes recurved; stamens 5, basally fused to and enclosed within corolla. Fruit a berry, 5–10 mm in diameter, glossy red or sometimes yellowish, borne inside an expanded calyx to >2 cm in diameter; seeds numerous.

Parts in Commerce: Root

Identification: The root of W. somnifera is a vertical taproot, 0.2–2.0(–3.5) cm thick, in cross-section showing a cork layer, a whitish starchy cortex, and a large central stele. Morphology is quite variable, and roots of cultivated plants are very different from roots of certain wild plants. Cultivated material has the following characters:

• Vertical taproot, to 30 cm long, straight to moderately curving, with few or no large lateral roots
• (0.2–)0.5–1.5(–3.5) cm thick
• Surface smooth or with slight longitudinal wrinkles, light brown to yellowish or whitish
• Root hairs few
• Texture soft
• Fracture short, even, “powdery”
• In cross-section, has cork layer, narrow whitish to cream starchy cortex, prominent brownish cambium ring, and large pale starchy central stele; xylem vessels mostly in a ring around outer edge of stele
• Cork thin, not separating from cortex, soft and easily powdered
• Odor characteristic, slightly pungent
• Taste bitter, acrid

Some wild populations have woody roots that, although belonging to the same species, display completely different characteristics. This material is considered unacceptable in commerce. Its features include the following:

• Often with many large lateral roots
• Frequently 2–3 cm in diameter
• Bark dark or reddish brown, sometimes prominently wrinkled, coarse, up to 3 mm thick and separating easily from cortex
• Stele containing lignified xylem throughout, making root woody and hard
• Odor strong

References:

Abedin S, Al-Yahya MA, Chaudhary SA, Mossa JS. Contribution to the flora of Saudi Arabia. Part II. A revision of the family Solanaceae. Pak J Bot. 1991;23:257–282.

Atal CK, Schwarting AE. Intraspecific variability in Withania somnifera. I. A preliminary survey. Lloydia. 1962;25:78–88.

Indian Drug Manufacturers’ Association. Indian Herbal Pharmacopoeia. Revised New Edition 2002. Mumbai, India: Indian Drug Manufacturers’ Association; 2002.

Sarin YK. Illustrated Manual of Herbal Drugs used in Ayurveda. New Delhi: Council of Scientific & Industrial Research and Indian Council of Medical Research; 1996.

Singh S, Kumar S. Withania somnifera. The Indian Ginseng. Ashwagandha. Lucknow, India: Central Institute of Medicinal and Aromatic Plants; 1998.

Symon DE. The solanaceous genera, Browalia, Capsicum, Cestrum, Cyphomandra, Hyoscyamus, Lycopersicon, Nierembergia, Physalis, Petunia, Salpichroa and Withania, naturalised in Australia. J Adelaide Bot Gard. 1981;3:133–166.