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.