New Triterpenoid Saponins from Ilex cornuta and Their Protective Effects against H2O2-Induced Myocardial Cell Injury

Five new triterpenoid saponins, 1-5, together with 10 known ones, 6-15 were isolated from the aerial parts of Ilex cornuta. The structures of compounds 1-5 were determined as 3 beta-O-alpha-L-arabinopyranosyl-19 alpha,23-dihydroxy-20 alpha-urs-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester, 1; 3 beta-O-beta-D-glucopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyl-19-hydroxy-20 alpha-urs-12-en-28-oic acid 28-O-beta-D-glucopyranosyl ester, 2; 19 alpha,23-dihydroxyurs-12-en-28-oic acid 3 beta-O-beta-D-glucuronopyranoside-6-O-methyl ester, 3; 19 alpha,23-dihydroxyurs-12-en-28-oic acid 3 beta-O-[beta-D-glucuronopyranoside-6-O-methyl ester]-28-O-beta-D-glucopyranosyl ester, 4; and 3 beta-O-[alpha-L-arabinopyranosyl-(1 -> 2)-beta-D-glucuronic acid]-oleanolic acid 28-O-beta-D-glucopyranosyl ester, 5, on the basis of spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR) and chemical reactions. Protective effects of compounds 1-15 were tested against H2O2-induced H9c2 cardiomyocyte injury, and the data showed that compounds 1, 4, 6, and 13 had significant cell-protective effects. No significant DPPH radical scavenging activity was observed for compounds 1-15.