Two new pregnane glycosides from the root of .

Two new pregnane glycosides ( and ), together with four known ones (- ), were isolated from the roots of Royle ex Wight (Asclepiadaceae). On the basis of detailed spectroscopic analysis and chemical method, the structures of new compounds were characterized to be metaplexigenin 3---D-cymaropyranosyl- (1→4)--L-diginopyranosyl-(1→4)--D-cymaropyranoside (), metaplexigenin 3---L-diginopyranosyl-(1→4)--D-cymaropyranoside (). All the isolated compounds (-) were tested for their inhibitory activity against the growth of human colon cancer cell lines HCT-116. Compounds and showed significant cytoxicities with IC values of 43.58 µM and 52.21 µM.