Synthesis of novel ring-A fused hybrids of oleanolic acid with capabilities to arrest cell cycle and induce apoptosis in breast cancer cells.

Six novel oleanolic acid ring-A fused hybrids (5-10) have been synthesized by employing a four step protocol with the introduction of benzylidene functionality at C-2 as the key step. Their structures were established by high resolution NMR and Mass spectral data. The synthesized compounds have been screened against seven human cancer cell lines including ME-180 & HeLa (cervix), MCF-7, MDA-MB-453 & MDA-MB-231 (breast), PC-3 (prostate) and HT-29 (colon) using MTT assay. Most significantly, compound 10 showed potent activity against the three breast cancer cell lines. The IC₅₀ value (10.60 μM) of compound 10 against MCF-7 found to be much lower than that of the standards and parent compound. Flow cytometric analysis reveals that compound 10 arrests cell cycle in S phase and induces apoptosis in MCF cells.