NEW DAMMARANE-TYPE GLYCOSIDES FROM GYNOSTEMMA-PENTAPHYLLUM

Four novel dammarane glycosides were isolated from a MeOH extract of the aerial parts of Gynostemma pentaphyllum. Their structures were elucidated by 1D and 2D nmr experiments, including H-1-H-1 correlation spectroscopy (COSY, HOHAHA, NOESY) and H-1-C-13 heteronuclear correlation (HETCOR). The aglycone moieties are the new dammarane-type triterpenes (20S)-3 beta,20,23 xi-trihydroxydammar-24-en-21-oic acid-21,23-lactone for 1, the corresponding epimer at C-20 (20R) for 2, (20S)-dammar-23-ene-3 Beta-20,25,26-tetraol for 3, and (20R)-dammar-25-ene-3 beta,20,21,24 xi-tetraol for 4.