Abstract: From acidic hydrolysate of crude glycoside of Gymnema yun-nanense Tsiang, four known C21 steroidal aglycones--penupogenin (1), 20-0-cinnamoylsarcostin (2), sarcostin ( 3 ) , metaplexigenin (5), and a new aglycone named gymnemarsgenin ( 4 ) were isolated. Compound (4) , colorless needle from MeOH, mp 155-157 °C, [α]D+ 145.96 (c =0.51, CHCl3). On the bases of EI-MS and elemental analysis, gave molecular formula; C37H4408 (M+, 616). Compoud (4) liberated sarco-stin (3) on alkaline hydrolysis.

Key words: Gymnema