Design and synthesis of novel cytotoxic podophyllotoxin derivatives

In order to investigate the effect of different C4 linkage moieties on the cytotoxicity of podophyllotoxin derivatives, novel 4-N- and 4-C-substituted 4＇-O-demethylepipodophyllotoxin derivatives were designed and synthesized. All the compounds were tested against A549 and MCF-7 tumor cells in vitro, and six compounds showed significant cytotoxicity. The most active compound 9f was superior to GL-331, and exhibited potent cytotoxicity with IC50 value at 10^-7 mol/L level.