Triterpenoid saponins from Ardisia gigantifolia.

Four new triterpenoid saponins (1-4) were isolated from the rhizome of Ardisia gigantifolia STAPF. The structures of new saponins were established as 3beta-o-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucopyranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl-16alpha-hydroxy-13,28-epoxy-oleanane (1), 3beta-o-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucopyranosyl-(1-->4)-[beta-D-glucopyrano-syl-(1-->2)]-alpha-L-arabinopyranosyl-16alpha-hydroxy-13,28-epoxy-30-acetoxy-oleanane (2), 3beta-o-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->2)]-beta-D-glucopyranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl-16alpha-hydroxy-13,28-epoxy-oleanane (3) and 3beta-o-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucopyranosyl-(1-->4)-[beta-D-6-O-acetylglucopranosyl-(1-->2)]-alpha-L-arabinopyranosyl-16alpha-hydroxy-13,28-epoxy-oleanane (4) were isolated from Ardisia gigantifolia STAPF. Their structures were elucidated by means of (1)H- and (13)C-NMR spectroscopic studies, including 2D-NMR technique. The cytotoxic activities of saponins 1-4 are reported against three human cancer cell lines, namely, Hela human cervical carcinoma cells, EJ human bladder tumor cells, and BCG-823 human gastric carcinoma cells.