Synthesis and biological evaluation of T-OA analogues as the cytotoxic agents

The lead compound T-OA, 3β-hydroxyolean-12-en-28-oic acid-(3,5,6-trimethylpyrazine-2-yl) methyl ester, which exhibited promising anticancer effects in vitro and in vivo, has previously been reported. According to the structural features, a series of novel T-OA analogues were synthesized via amino condensation reaction. These analogues’ cytotoxic activities were evaluated on five cancer cell lines (Bel-7402, HepG-2, HT-29, Hela, BGC-823) and hepatic stellate cell line (HSC-6). Among the candidates, compounds 8 and 16 showed promising effects; 3β-hydroxy-lup-20(29)-ene-28-oic acid-(3,5,6-trimethylpyrazin-2-yl) methyl amine (16) even possessed superior bioactivities to positive drugs (cisplatin and ursolic acid), which was worthy of further study. In addition, structure–activity relationships and Clog P values of T-OA analogues were briefly discussed.