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.
Figure 85: Withania somnifera cultivated root cross-section.