Two new polyoxypregnane glycosides, mucronatoside A (l) and mucronatoside B (2), together with one known stephanoside E (3) were obtained from the stems of Stephaiwtis mucronata (Blanco) Merr. (Asclepiadaceae). Their structures were elucidated as 12-tigloxyl-20-O- acetoxyl sarcostin 3-0-β-thevetopyranosyl-( 1→4 )-β-cymaropyranosyl- ( 1→4 )-β-cymaropyranoside (1); 5,6-dihydro-12-0-acetoxy-2O-O- tigloxyl sarcostin 3-0-β-thevetopyranosyl-(1→4) -β-cymaropyranosyl- (1→4)-β-cymaropyranoside (2); 12- 0-acetoxy-2O- O- ( A'-methyl) anthraniloyl sarcostin 3-0-β-thevetopyranosyl-( 1 → 4 )-β- cymaropyranosyl-( 1→4 )-β-cymaropyranoside ( 3 ), respectively, on the basis of spectroscopic and chemical means.

Key words: Stephanotis mucronata, STEROIDS, PYRANOSE, GLYCOSIDE, ISOLATION, STRUCTURE