Cytotoxic cardenolides and antibacterial terpenoids from Crossopetalum gaumeri

Abstract

From the methanol extract of the roots of Crossopetalum gaumeri, four new highly cytotoxic cardenolides, securigenin-3β- O-β-6-deoxyguloside (2). 19-hydroxy-sarmentogenin-3β-O-β-6- deoxyguloside (4). sarmentogenin-3β-O-[α-allosyl-(1 → 4)-β-6- deoxyalloside] (5). and securigenin-3β-O-[α-allosyl(1 → 4)-β- 6-deoxyalloside] (6) were isolated. The dichloromethane extract afforded the new diterpene 3,15-dihydroxy-18-norabieta-3,8,11,13- tetraene (7) as well as the new triterpene 2,3,7-trihydroxy-6- oxo-1,3.5(10),7-tetraene-24-nor-friedelane-29-oic acid methylester (11). The new terpenoids lack cytotoxicity and the antibacterial activity is moderate to low. (C) 2000 Elsevier Science Ltd.