A pregnane glycoside from the roots of Mandevilla pentlandiana.

A pregnane triglycoside containing a new genin 3 beta,14 beta-dihydroxy-21-methoxy-5 beta-pregnan-20-one has been isolated from the dried roots of Mandevilla pentlandiana. Chemical and spectroscopic evidence for the glycoside are consistent with the structure 3 beta, 14 beta-dihydroxy-21-methoxy-5 beta-pregnan-20-one-3-O-beta-D- diginopyranosyl-(1----4)-O-beta-D-cymaropyranosyl-(1----4)-O -beta-D-cymaropyranoside. It is noteworthy that 3 beta,14 beta,21-trihydroxy 5 beta-pregnan-20-one, biosynthetically related to the genin of this glycoside, has been proved to be a precursor of cardenolides, also produced by this plant.