Triterpene saponins from the roots of Ilex asprella

Six new triterpene saponins, ilexasprellanosides A-F (1-6, resp.), together with eleven known compounds were isolated from the roots of Ilex asprella. The new saponins were characterized as ursa-12,18-dien-28-oic acid 3-O-β-D-xylopyranoside (1), 19α-hydroxyursolic acid 3-O-β-D-(2'-O-acetylxylopyranoside) (2), 19α-hydroxyursolic acid 3-O-β-D-glucuronopyranoside (3), 3β,19α-dihydroxyolean-12-en-23,28-dioic acid 28-O-β-D-glucopyranoside (4), 19α-hydroxyoleanolic acid 3-O-β-D-(2'-O-acetylxylopyranoside) (5), 19α-hydroxyoleanolic acid 3-O-β-D-glucuronopyranoside (6). The structures of the new compounds were elucidated by analysis of their spectroscopic data and chemical degradation. Compounds 2, 4, oleanolic acid 3-O-β-D-glucuronopyranoside, 3-β-acetoxy-28-hydroxyurs-12-ene, and pomolic acid showed significant cytotoxic activities against human tumor cell line A549 (IC50 values of 1.87, 2.51, 1.41, 3.24, and 5.63 μM, resp.).