Two new and two known triterpenoid saponins were isolated from the stem bark of Pentaclethra macroloba. Their structures were determined using a combination of homo- (1D ¹H NMR, 13C NMR-HBBD and 13C NMR-DEPT) and heteronuclear 2D NMR techniques (¹H-¹H-COSY, ¹H-¹H-TOCSY, ¹H-¹H-NOESY, HMQC and HMBC), ESIMS and chemical methods. The structures of the two new pentacyclic triterpenoid saponins were established as 3beta-O-{[beta-D-glucopyranosyl-(1->3)-alpha-L-rhamnopyranosyl-(1->2)],beta-D- glucopyranosyl-(1->4)}-alpha-L-arabinopyranosylhederagenin (3) and 3beta-O-{[beta-D-glucopyranosyl-(1->4)-beta-D-glucopyranosyl-(1->3)-alpha-L-rhamnopyranosyl- (1->2)],beta-D- glucopyranosyl(1->4)}-alpha-L-arabinopyranosyloleanolic acid (4).
Pentaclethra macroloba; Mimosoideae; pentacyclic triterpenoid saponins
