[Saponins from Thinouia coriacea]

The investigation of the stems of Thinouia coriacea Britton (Sapindaceae), an ichthyotoxic plant from South Brazil, afforded eight glycosides of oleanolic acid. Structures were assigned based on data from partial hydrolysis. 13C-NMR and mass spectral procedures as 3-O-alpha-L-arabinopyranoside (1), 3-O-alpha-L-rhamnopyranosyl-(1----2)-alpha-L-arabinopyranoside+ ++ (2), 3-O-beta-D-glucopyranosyl-(1----4)-alpha-L-arabinopyranoside (3), 3-O-beta-D-glucopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1----2 )-alpha-L-arabinopyranoside (4), 3-O-alpha-L-rhamnopyranosyl-(1----2)[beta-D-glucopyranosyl-(1----4 )]-alpha-L-arabinopyranoside (5), 3-O-beta-D-xylopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1----2) [beta-D-glucopyranosyl-(1----4)[alpha-L-arabinopyranoside (6), 3-O-beta-D-glucopyranosyl-(1----3)-alpha-L-rhamnopyranosyl-(1----2 )[beta-D-glucopyranosyl-(1----4)]-alpha-L-arabinopyranoside (8). Saponin 7 showed the same sugars as 8, but the attachment between the sugars could not be elucidated. The same saponins were present in the roots, but not in the leaves.