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 3β-O-α-L-arabinopyranosyl-19α,23-dihydroxy-20α-urs-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester, 1; 3β-O-β-D-glucopyranosyl-(1→2)-α-L-arabinopyranosyl-19-hydroxy-20α-urs-12-en-28-oic acid 28-O-β-D-glucopyranosyl ester, 2; 19α,23-dihydroxyurs-12-en-28-oic acid 3β-O-β-D-glucuronopyranoside-6-O-methyl ester, 3; 19α,23-dihydroxyurs-12-en-28-oic acid 3β-O-[β-D-glucuronopyranoside-6-O-methyl ester]-28-O-β-D-glucopyranosyl ester, 4; and 3β-O-[α-L-arabinopyranosyl-(1→2)-β-D-glucuronic acid]-oleanolic acid 28-O-β-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.