Six new triterpenoid saponins from the root and stem bark of Cephalanthus occidentalis

From the root and stem bark of Cephalanthus occidentalis L., a common American wetland species, six new triterpenoid saponins (1 - 6), together with 29 known compounds were isolated and identified. On the basis of spectroscopic analysis and chemical degradation, the structures of new compounds were elucidated as 3-O-beta-glucopyranosylcincholic acid (1), cincholic acid 28-O-beta-glucopyranosyl ester (2), 3-O-beta-glucopyranosyl-(1-->4)-beta-fucopyranosylcincholic acid (3), 3-O-beta-glucopyranosyl-(1-->4)-beta-fucopyranosylcincholic acid 28-O-beta-glucopyranosyl ester (4), 3-O-beta-glucopyranosylcincholic acid 28-O-alpha-arabinopyranosyl-(1-->2)-beta-glucopyranosyl ester (5), and 3-O-beta-glucopyranosylquinovic acid 28-O-alpha-arabinopyranosyl-(1-->2)-beta-glucopyranosyl ester (6).