Inhibitory Effect of Triterpenoid Saponins from the Leaves of Ilex kudingcha on Aggregated LDL-Induced Lipid Deposition in Macrophages

We have investigated the inhibitory effect of triterpenoid saponins from the leaves of flex kudingcha C.J. Tseng on aggregated low-density lipoprotein (LDL)-induced lipid deposition in macrophages. A cell-based screening model was initially applied on aggregated LDL (aggLDL)-induced lipid deposition on macrophages to test the inhibitory effects of the 12 triterpenoid saponins from this plant. Eight of these compounds inhibited the formation of foam cells and reduced intracellular total cholesterol and triglyceride contents. Structure-activity relationship analysis showed the essential role of the delta-lactone ring for the biological activity. The promoter action of the OH group at the C-12 position, the number of monosaccharides in the sugar chain and the rhamnose at the terminal of the sugar chain is also discussed.