Alkylidene branched lupane derivatives: Synthesis and antitumor activity

Several novel alkylidene branched lupane derivatives have been prepared. Many of these compounds showed a significant cytotoxicity. The most active compound, 2-methylene-betulonic acid, showed IC50 values between 0.2 and 0.6 mu M for 15 different human cancer cell lines. Cytotoxicity can be improved by encapsulation in liposomes. These compounds act by triggering apoptotic cell death as shown by DNA-laddering experiments and acridine orange/ethidium bromide staining. (C) 2012 Elsevier Masson SAS. All rights reserved.