Lupane triterpenes with a carbonyl group at C-20 induce cancer cell apoptosis.

We evaluated the effects of various lupane triterpenes on B16 2F2 mouse melanoma cell differentiation and proliferation. All of the compounds tested (numbered 1-6) induced melanogenesis of B16 2F2 cells, a marker of melanoma cell differentiation. Compounds 4-6, which have a carbonyl group at C-20, markedly inhibited the growth of B16 2F2 cells by the induction of apoptosis. Cytotoxic profiles of these lupane triterpenes against human cancer cells demonstrated that compounds 4-6 showed inhibitory effects on the proliferations of leukemia and lung cancer cells, to a greater extent than other cancer and normal fibroblast cells. These results suggest that the carbonyl group at C-20 of lupane triterpenes played important roles in their apoptosis-inducing activity against cancer cells.