Withanis somifera - a Source of Exotic Withanolides

Abstract

Withania sornnifera has yielded three new withanolides somnifericin (1).2.3-dkhydrosomnifericin (21, and withaoqlactone (3).Withanolides are steroidal lactones, the first of which, withaferin A, was isolated from the leaves of Withania sornnifera in 1956.Since then a large number of withanolides have been isolated from different species of Withania, Physalis and Datura.Some of these were found to have antitumor.cytotoxic and antimicrobial activities.l.2Our studies have revealed that W. sornnifera ramains a rich source of interesting new withanolides with potentially useful biological activities2During our investigations on withanolidal constituents of family Solanaceae, we examined the organic extracts of the plants of genus Withania and isolated several new ~i t h a n o l i d e s .~In this paper we describe the isolation of three compounds (1, 2, and 3) from W. sornnifera, whose structures were determined by using spectroscopic techniques.Compound (1) was isolated from the defatted methanolic extract of the whole plant of W. sornnifera.The high-resolution electron-impact mass spectrum (HREIms) afforded the molecular ion at rn/z 490.2929 establishing the molecular formula as C28H4207 (calcd 490.2930) indicating eight degrees of unsaturation in the molecule.The M+ was further confirmed by positive FAB ms data.The uv spectrum showed absorption at 225 nm indicating the presence of an a,P-unsaturated lactone.3The ir spectrum displayed bands at 3340, 1725, 1700, and 1665 cm-I from which the presence of hydroxylic group.a,P-unsaturated lactone, ketone, and double bond in the molecule could be inferred.