Design, synthesis and in vitro anticancer activity of novel quinoline and oxadiazole derivatives of ursolic acid.

A series of new quinoline derivatives of ursolic acid were designed and synthesized in an attempt to develop potential anticancer agents. The structures of these compounds were identified by 1 H NMR, 13 C NMR, IR and ESI-MS spectra analysis. The target compounds were evaluated for their in vitro cytotoxicity against three human cancer cell lines (MDA-MB-231, Hela and SMMC-7721). From the results, compounds 3a – d displayed significant antitumor activity against three cancer cell lines. Especially, compound 3b was found to be the most potent derivative with IC 50 values of 0.61 ± 0.07, 0.36 ± 0.05, 12.49 ± 0.08 μM against MDA-MB-231, HeLa and SMMC-7721 cells, respectively, stronger than positive control etoposide. Furthermore, the Annexin V-FITC/PI dual staining assay revealed that compound 3b could significantly induce the apoptosis of MDA-MB-231 cells in a dose-dependent manner. The cell cycle analysis also indicated that compound 3b could cause cell cycle arrest of MDA-MB-231 cells at G0/G1 phase. [ABSTRACT FROM AUTHOR]