Polyoxypregnane Glycosides from the Roots of Marsdenia tenacissima and Their Anti-HIV Activities.

A continuous phytochemical study on the roots of led to the isolation and identification of 13 new polyoxypregnane glycosides named marstenacissides B10-B17 (, and ) and marstenacissides A8-A12 (, and ) in addition to two known polyoxypregnane glycosides marsdenosides M and L ( and ). Their structures were established by spectroscopic techniques and by comparison with the reported data in the literature. Moreover, the anti-HIV activities of these isolates and the previous isolated marstenacissides A1-A7 and B1-B9 were assessed, some of which exhibited slight or negligible effects against HIV-1.