Synthesis and antitumor activity evaluation of novel ursolic acid derivatives

Eleven novel ursolic acid (UA) derivatives were designed and synthesized with modification at positions of C-2, C-3, and C-28 of UA. Their structures were confirmed by MS, 1H NMR, and elemental analysis. Their in vitro cytotoxicities against various cancer cell lines (HeLa, HepG2, and BGC-823) were evaluated by MTT assay. The results indicated that all compounds could inhibit cell proliferation of HeLa, HepG2, and BGC-823 cells. Among them, compounds I3 and I4 showed more potent cytotoxicity on these three tumor cells than gefitinib (positive control), worthy to be studied further.