Synthesis and preliminary anti-tumor activity of novel ursolic acid derivative-chalcone conjugates

Ten novel conjugates with ursolic acid core and different chalcone ligands were synthesized via esterification using the natural ursolic acid as starting material. The structures of these conjugates were confirmed by ¹H NMR, ¹³C NMR and HRMS. The preliminary biological results showed that these compounds displayed significant antiproliferative effect on CNE2, KB, MCF-7, A549 and HepG2 cells. These compounds were more effective than ursolic acid and tamoxifen against MCF-7 cells. Especifically, compound 11e (IC₅₀=4. 7 μmol/L)showed the greatest potency against MCF-7, which was about 3-times more potent than tamosifen(IC₅₀=15. 2 μmol/L). Additionally, all conjugates were nontoxic to health MCF-10A and VERO cells, and had higher security than tamoxifen.