Studies on the constituents of Actinostemma lobatum Maxim. I Structures of actinostemmosides A, B, C and D, dammarane triterpene glycosides isolated from the herb.

Abstract

From the dried herb of Actinostemma lobatum MAXIM. (Cucurbitaceae), four dammarane-type triterpene glycosides named actinostemmosides A, B, C and D were isolated and their structures were elucidated on the basis of chemical and spectral evidence. Actinostemmosides A, B and C were identified as 20-Ο-β-D-glucopyranosides of 3β, 6α, 20, 27-tetrahydroxy- (20S) -dammar-24-ene, 3β, 7β, 20, 27-tetrahydroxy- (20S) -dammar-24-ene and 3β, 7β, 18, 20, 27-pentahydroxy- (20S) -dammar-24-ene, respectively, and actinostemmoside D, as the α-L-rhamnopyranosyl- (1→2) -β-D-glucopyranoside of 3β, 6α, 20, 27-tetrahydroxy- (20R) -dammar-24-ene.