Clionasterol Glucoside and Acylated Clionasterol Glucosides from Oplismenus burmannii

A new clionasterol glucoside, clionasterol‐[(1'→3α)‐ O ‐β‐D]‐glucopyranoside ( 1 ), a new acylated clionasterol glucoside, clionasterol‐[6'‐ O ‐acyl‐(1'→3β)‐O‐b‐D]‐glucopyranoside ( 2 ) and clionasterol ( 3 ) were isolated from the aerial parts of Oplismenus burmannii . The nature and length of fatty acid acyl chains in 2 was identified by alkaline methanolysis of compound 2 . The aglycone fraction on GC‐MS analysis showed three peaks in GC at t R 49.86 (82.1%), 51.13 (13.3%) and 56.53 (4.6%) min, which were characterized as arachidic acid methyl ester ( a ) oleic acid methyl ester ( b ) and 12‐methyltetradecanoic acid methyl ester ( c ) respectively. Thus 2 was characterized as a mixture of three new compounds, clionasterol‐[6'‐ O ‐eicosanoyl‐(1'→3β)‐ O ‐β‐D]‐glucopyranoside ( 2a ), clionasterol‐[6'‐ O ‐(8Z)‐octa‐deca‐9‐enoyl‐(1'→3β)‐ O ‐β‐D]‐glucopyranoside ( 2b ) and clionasterol‐[6'‐ O ‐(12‐methyltetradecanoyl)‐(1'→3β)‐ O ‐β‐D]‐glucopyranoside ( 2c ).