Cholestane steroid glycosides from the rhizomes of Dioscorea villosa (wild yam).

Phytochemical investigation of the MeOH extract of Dioscorea villosa rhizomes resulted in the isolation of two new bidesmosidic cholestane steroid glycosides, dioscoreavillosides A and B (1 and 2). In addition, the extract yielded 12 previously known furostan and spirostan steroid glycosides (3-14), along with diosgenin (15). Compounds 3-7, 9, 14, and 15 were isolated for the first time from D. villosa. The structures of the isolated compounds were determined using spectroscopic and chemical methods including 1D and 2D NMR. The antimicrobial action of most of these compounds was tested against five fungal and five bacterial strains.