Triterpenoid saponins from Gymnema sylvestre.
Besides six known gymnemic acids, four new tritepenoid saponins, gymnemasins A, B, C and D, isolated from the leaves of Gymnema sylvestre, were identified as 3-O-[beta-D-glucopyranosyl(1-->3)-beta-D-glucuronopyranosyl]-22-O- tigloyl- gymnemanol, 3-O-[beta-D-glucopyranosyl (1-->3)-beta-D-glucuronopyranosyl]-gymnemanol, 3-O-beta-D-glucuronopyranosyl-22-O-tigloyl-gymnemanol and 3-O-beta-D-glucuronopyranosyl-gymnemanol, respectively. The aglycone, gymnemanol, which is a new compound, was characterized as 3 beta, 16 beta, 22 alpha, 23, 28-pentahydroxyolean-12-ene.