Buxaustroines A-N, a Series of 17(13→18)-Cycloartenol Triterpenoidal Alkaloids from and Their Cardioprotective Activities.

Buxaustroines A-N (-), a series of triterpenoidal alkaloids featuring a novel 17(13→18) motif, were obtained from the extract of . Their structures were assigned based on NMR data analysis and X-ray diffraction crystallography. A putative biosynthetic pathway for one of the alkaloids from a co-isolate is proposed. In the assessment of their bioactivities, some of the compounds displayed protective effects against doxorubicin-induced injury of myocardial cells. Preliminary structure-activity relationship studies of -, which are based on the same skeleton, were conducted.