Structure-activity relationship of Triterpenes and derived Glycosides against cancer cells and mechanism of apoptosis induction.

Triterpenoids possess a wide range of biological effects. Here, the cytotoxic activities of 55 triterpenes and derived glycosides against BEL-7404 and SGC-7901 cells were assessed, and structure-activity relationships were analysed accordingly. Nine of them effectively inhibited the two cell lines. In particular, compounds 49 and 52 inhibited BEL-7404 cells as efficiently as 5'-fluorouracil (IC50 values 0.46 and 1.48, respectively). Moreover, we found that compounds 49 and 52 induced apoptosis in BEL-7404 cells. Indeed, DNA fragmentation assay showed a time-dependent degradation of DNA after treatment of cells with compounds 49 and 52. In addition, Bax gene expression levels were increased after treatment with these compounds, in a concentration-dependent manner. Taken together, our findings suggested that compounds 49 and 52 induce apoptosis in BEL-7404 cells by upregulating the Bax gene without affecting Bcl-2 gene expression.