Withanolides - much talked natural product
Author: Dr Amrit Pal Singh, MD (Alternative Medicine), Medical Executive, Ind -Swift Ltd Super Speciality Divison. Email
Ashwagandha (Withania somnifera) is a reputed drug of Ayurveda. It finds application in Ayurvedic formulation for impotency and arthritis. Withania somnifera is an erect evergreen shrub that grows to about 1.5 meters in height in drier regions of India. It has been used for as sedative, diuretic and anti-inflammatory properties agent Modern studies have thrown light on immunomodulatory and anti carcinogenic activity of the plant and it has been rightly called as 'Indian ginseng'.
Withania somnifera contains alkaloids and a special group of compounds called withanolides, which are considered to be the active principles of the drug. Chemically, withanolides are a group of naturally occurring oxygenated ergostane type steroids having lactone in side chain and 2-en-1-one system in ring A. The withanolides are present in the whole of the plant, but maximum presence have been recorded from the leaves. Withaferin-A is the important withanolide isolated so far.
Withaferin- A has shown potent tumor-inhibiting activity in Ehrlich ascites carcinoma, Sarcoma 180, Sarcoma Black (SBL), and E 0771 mammary adenocarcinoma in animal models. Besides it, Withaferin-A has significant anti-arthritic and anti-inflammatory activities. Other withanolides have demonstrated immuno-modulator, cardio-vascular and antifungal activity. 3-B-hydroxy, 2-3 dihydrowithanolide has a significant protective effect in rats against carbon tetrachloride induced hepatic damage.
The standardization of Withania somnifera is based on withanolide content and the drug should contain 1.5% w/w of withanolide. Withanolides are present in other members of Solaneace like Physalis minima, Nicandra physaloides, Physalis philadelphica, Solanum torvum, Datura innoxia and Datura metel L.The withanolides present in other plant include Withametelin, withacoagin, coagulin, and withasomidienone, 3-dihydro-3-methoxywithaphysacarpin (1), and two known compounds, withaphysacarpin, 24,25-dihydrowithanolide D, Withanicandrin, Withaphysalin- A and Withaphysalin -B.
References :
1. Tripathi, A.K. Shukla, Y.N. & Kumar, S. (1996). Ashwagandha (Withania somnifera): a status report 1996î J.Med Arom Plant Sci; 18:46 -52.
2. Asthana, R and Raina, M.K., (1989). Pharmacology of Withania somnifera- a review. Ind. Drugs; 26: 1-7.
3. Subhir, S. et-al., (1978). Pharmacological investigation on the leaves of Withania somnifera. Ind. J. Pharmacol; 17:44-52.
4. Antitumor and radiosensitizing effects of Withania somnifera (Ashwagandha) on a transplantable mouse tumor, Sarcoma-180. In: Indian J Exp Biol (1993 Jul) 31(7): 607-11.
5. Gupta, A. P., R. K. Verma, et al. (1996). Quantitative determination of withaferin. A in different plant parts of Withania somnifera by TLC densitometry. Journal of Medicinal and Aromatic Plant Sciences 18(4): 788-790. {a} Central Inst. Med. Aromatic Plants, Lucknow 226 015, India.
6. Ziauddin, M., N. Phansalkar, et al. (1996). Studies on the immunomodulatory effects of Ashwagandha. Journal of Ethnopharmacology 50(2): 69-76. {a} Interdisciplinary School Health Sciences, University Pune, Pune 411 007, India.