Ahttac!-Two new withanolides, sominone (la, 3B,27-trihydroxy-22 (R)-witha-5,24-dienolide)(1) and sominolide (4B.27-dihydroxy-14a,l5a-epov-1-0x0-22-(R)-witha-2, 24-dienolide) (2) were isolated from the herbs of Wuhaniasomn$era Dun.(Solanaceae).The elucidation of their structures is based on extensive spectroscopic studies.A number of highly oxygenated C-28 steroidal lactones have been isolated from various genera of the plant family Solanaceae including WithMia, AcnirhLF, Datura, Jaborosa, Lycium, Nicardra and ~hysalis.~These compounds have considerable phytochernical, chemotaxonomic and medicinal interest2 Two species of the genera Wuhania i.e.Withania somnifea and U? coagulans are commonly found in Pakistan and are claimed to have uses in the indigenous system of medicine for the treatment of ulcers, tumors, tubercular glands, carbuncles, as diuretic and antipyretic.ls2In continuation of our interest on medicinal plants of Pakistan, we have investigated the chemical constituents of Wdhania somnifera The present investigation on the ethanolic extracts of the herbs of W. somnifera revealed the presence of two new withanolides, sominone (1) and sominolide (2).Sominone (I), C ~4 2 0 5 , showed a uv absorption maximum at 215 nm, characteristic of an a, B-unsaturated lactone c h r ~m o ~h o r e .~ The ir spectrum displayed intense absorptions at 1710 (a$-unsaturated lactone) and 3500 (0-H) an-'.The high-resolution electron impact mass spectrum of 1 showed the molecular ion at d z 458.3051 corresponding to the molecular formula Cz8H420s (calcd 458.3032), indicating the presence of eight double bond equivalents in the molecule.Considerably strong peaks at d z 440 and 422 were due to the loss of one and two water molecules respectively.The ion at d z 169.0851 of composition C9H1303 resulted by the cleavage of the C-17lC-20 bond and indicated the presence of a six-membered lactone
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Rahman et al. (1992) studied this question.