Radix Withaniae

Definition

Radix Withaniae consists of the dried roots of Withania somnifera (L) Dunal. (Solanaceae).

Synonyms

Physalis somnifera L.

Selected vernacular names

Achuvagandi, agol, ahan, aksin, amukkuram, amukkaramkizangu, amukkira,angarberu, a sh a ga n dha, asagand, asagandh, asagandh nagori, asagandha, asan, asana, askagandha as’vagandha, ashvagandha, ashvakandika, ashwaganda, ashwagandha, ashwaganha, asgand, asgandh, asgandha, asganhisrol, asoda, asun, asundha, asunyho, asuvagandi, asvagandha, asvagandhi, aswagandha, aswal, aswgandh, babu, bâibru, bouzidân, dambarico, ghoda,ghodakun,ghodasan, gisawa, gizawa, hayagandhã, hidi-budawa, hirchil, e-gaddy, hiremaddina-gaddy, hiremaddina-gida, Indian ginseng, juustumari, kakani hindi, kaknaj-e-hindi, kilangee, kuvia, lakri, ol asajet, oroval, penneru, pennerugadda, punir, samoah, sebbere-gola, sim-alfirakh, sum-ul-far, sum-ul-firakh, techil, ubab, u’beb, ubuvimba, vajigandha, winter cherry, withania.

Description

Description

A woody herb or shrub, up to 2 m in height; growing from a long, tuberous taproot; stellatetomentose.

Leaf: simple, 2–11 cm in length by 1.5–9.0 cm in width, exstipulate, petiole 6–20 mm long; blade elliptic to ovate-lanceolate, apex acute or rounded, base acute to long-decurrent, on vegetative shoots 8–10 cm long and alternate, on reproductive shoots 3–8 cm long and opposite, arranged in pairs of one large and one smallerleaf; margin entire or wavy. Inflorescence: axillary, umbellate cyme of 2–25 yellow-green, short-pedicellate flowers.

Flower: perfect, radially symmetrical, campanulate; calyx with 5 acute triangular lobes; corolla twice the length of the calyx, 7–8 mm long, with 5 lanceolate lobes, spreading or reflexed; stamens 5, slightly exserted, filaments alternate to petal lobes, partially fused to corolla; ovary superior, glabrous, stigma shallowly bifid.

Fruit: berry; globose, 5–6 mm in diameter, orange-red, enclosed in green, membranous, inflated calyx approximately 2.5 cm in diameter and slightly 5-angled.

Seeds: many, discoid, 2.5 mm in diameter, pale yellow.

General appearance

General appearance

Straight and unbranched, the thickness varying with age.

The main roots bear fibre-like secondary roots.

The outer surface of the root is buff to grey-yellow with longitudinal wrinkles. The crown consists of 2–6 remains of the stem base.

The base of the stem is green, variously thickened, cylindrical and longitudinally wrinkled. The roots break with a short uneven fracture.

Organoleptic properties

Odour: characteristic, horse-like; taste: sweetish, yet bitter and astringent and slightly mucilaginous.

Microscopic characteristics

The transverse section shows a narrow band of yellowish cork, exfoliated or crushed, a narrow cortex packed with starch grains; cork cambium of 2–4 diffused rows of cells; secondary cortex about 24 layers of compact parenchymatous cells; phloem consists of sieve tube, companion cells, phloem parenchyma; cambium 4–5 rows of tangentially elongated cells; secondary xylem hard, forming a closed vascular ring separated by multiseriate medullary rays; a few xylem parenchyma.

Powdered plant material

Dusty white or grey to yellow-brown.

Cork thin-walled; lignified, cubical or elongated cells, often indistinct and collapsed, with yellowish-brown contents; 2–3 cells deep in smaller roots, up to 16 in larger primary roots.
Parenchyma of the cortex composed of large thin-walled cells, packed with starch granules, and occasionally containing microsphenoidal crystals of calcium oxalate.

Xylem elements are either tracheidal with bordered pits or, more rarely, reticulately thickened vessels.

Fibres from xylem have thickened lignified walls and simple pits.

Starch abundant, simple or 2–4-compound, with a pronounced irregularly shaped hilum.

Medicinal uses

Medicinal uses

Uses supported by clinical data

As an antistress agent to improve reaction time.

Uses described in pharmacopoeias and well established documents

As a general tonic to increase energy, improve overall health and prevent disease in athletes and the elderly.

Uses described in traditional medicine

Treatment of bronchitis, dyspepsia, impotency, scabies and ulcers.

Pharmacology

Pharmacology

Experimental pharmacology

Antistress activity

The activity of a standardized extract of the root (1:1 aqueous ethanol fraction containing the withanolide glycosides and withaferin A at a concentration of 28-30%) was investigated in a rat model of chronic stress.

A mild, unpredictable foot-shock was administered once daily for 21 days to rats.

These chronic stress-induced perturbations were attenuated by the intragastric administration of the crude drug, at a dose of 25.0 and 50.0 mg/kg body weight (bw) given 1 h before foot-shock for 21 days.

In a mouse model of chronic stress, the antioxidant effects of the root were assessed in the forced swimming test.

Biochemical analysis revealed that chronic swimming significantly increased lipid peroxidation and decreased glutathione levels in the brains of mice.

The animal models also showed decreased levels of antioxidant defence enzymes, superoxide dismutase and catalase. Intragastric treatment with an extract of the crude drug, at a dose of 100.0 mg/kg bw significantly reduced lipid peroxidation and restored the glutathione levels decreased by chronic swimming in mice.

Further, the treatment increased levels of superoxide dismutase in the forebrain and increased levels of catalase.

A withanolide-free aqueous fraction from the root (13 kg plant material in 70% ethanol, aqueous fraction) was evaluated for putative antistress activity.

Intragastric administration of the preparation to immunocompromised mice for 7 days increased antibody production with a median effective dose of 40 mg/kg bw. Thus, the fraction exhibited significant antistress activity in a dose-related manner. The same fraction was protective against chemically and physically induced stress in rats and mice.

Intragastric administration of sitoindosides IX and X, at a dose range of 50–200.0 mg/kg bw also produced antistress activity in albino mice and rats, and augmented learning acquisition and memory retention in both young and old rats.

Clinical pharmacology

A double-blind, placebo-controlled clinical trial assessed the effects of the root (250 mg twice daily) on psychomotor performance in 30 healthy volunteers.

The effects were compared with those of Panax ginseng (100 mg twice daily). Test parameters included tapping, cancellation test, mental mathematical calculations, logical deductions, choice reaction times and auditory reactions. The performance of both groups was superior to that of subjects who received a placebo and the performance of subjects given the crude drug was superior to that of those given Panax ginseng after 40 days of treatment.