Cytotoxic cardenolides and antibacterial terpenoids from Crossopetalum gaumeri

From the methanol extract of the roots of Crossopetalum gaumeri, four new h ighly cytotoxic cardenolides, securigenin-3 beta-O-beta-6-deoxyguloside (2) , 19-hydroxy-sarmentogenin-3 beta-O-beta-6-deoxyguloside (4), sarmentogenin -3 beta-O-[alpha-allosyl-(1 --> 4)-beta-6-deoxyalloside] (5), and securigen in-3 beta-O-[alpha-allosyl-(1 --> 4)-beta-6-deoxyalloside] (6) were isolate d. 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-trihy droxy-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 i s moderate to low. (C) 2000 Elsevier Science Ltd. All rights reserved.