Antiproliferative Effects of Saponins from the Roots of Platycodon grandiflorum on Cultured Human Tumor Cells

Three new triterpenoid saponins, platyconic acid B lactone (1), deapio-platyconic acid B lactone (2), and deapio-platycodin D2 (3), together with 17 known triterpenoid saponins, were isolated from a root extract of Platycodon grandiflorum. The structures of 1−3 were determined on the basis of spectroscopic data interpretation and chemical transformation. Saponins with a platycodigenin or polygalacic acid unit as a sapogenin demonstrated significant inhibitory effects on the proliferation of a small panel of cultured human tumor cells.