XANTHINE-OXIDASE INHIBITORS FROM THE ROOTS OF EGGPLANT (SOLANUM-MELONGENA L)

Stigmasterol 1, stigmasterol-beta-D-glucoside 2, beta-sitosterol-beta-D-glucoside 3, dioscin 4, protodioscin 5 and methyl protodioscin 6 were isolated and characterized from the butanol soluble part of the ethanolic extract of eggplant roots (Solanum melongena L. Solanaceae). Except for stigmasterol, these compounds have not been previously isolated from Solanum melongena L. Since the roots of the eggplant have been used in folk medicine for rheumatism, inflammation and foot pain1,2 these compounds were tested for their inhibitory effect on xanthine oxidase. The results showed that the phytosterols 1, 2 and 3 displayed a stronger inhibition on xanthine oxidase than the steroidal glycosides 4, 5 and 6. From the structural features, the active moiety seems to be the double bond for both phytosterols and steroidal glycosides or 22-OH group in furostanol glycoside 5 as regards xanthine oxidase inhibition based on this study.