Studies on the constituents of Clematis species. VIII triterpenoid saponins from the aerial part of Clematis tibetana kuntz

Abstract

From the aerial part of Clematis tibetana, two new hederagenin 3,28-0-bisdesmosides called clematibetosides A and C, and a new gypsogenin 3,28-0-bisdesmoside called clematibetoside B, have been isolated together with ten known saponins. The structures of the new saponins have been elucidated based on chemical and spectral evidence as follows: clematibetoside A, 3-0-(2-0-caffeoyl)-β-D-glucopyranosyl-(1→4)-β-D- glucopyranosyl(1→4)-β-D-ribopyranosyl-(1→3)-→-L- rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl hederagenin 28-0-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl- (1→6)-β-D-glucopyranoside; clematibetoside B, 3-0-α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl gypsogenin 28-0-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)- β-D-glucopyranoside; clematibetoside C, 3-0-β-D-ribopyranosyl hederagenin 28-0-α-L-rhamnopyranosyl-(1→4)- β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside.