Conjugation of Uridine with Oleanolic Acid Derivatives as Potential Antitumor Agents.

According to fused two bioactive moieties together by bonds covalently and available as a new single hybrid entity known as pharmacophore hybridization, a total of 10 targeted uridine-oleanolic acid hybrids were synthesized. Most of these hybrids showed excellent proliferation inhibition against tested Hep-G2, A549, BGC-823, MCF-7, and PC-3 tumor cell lines (IC50 < 8 μm), even with some IC50 values under 0.1 μm. The detection of cytotoxicity selectivity revealed that hybrids 5 and 18 exhibited low cytotoxicity toward normal human liver cell HL-7702. Further studies revealed that selected hybrid 5 could induce apoptosis in Hep-G2 cells through the investigation of acridine orange/ethidium bromide, Hoechst 33258 fluorescence stainings, and annexin V/propidium iodide assay. It was also found that hybrid 5 could induce mitochondrial membrane potential disruption, arrest Hep-G2 cell line at G1 phase, and activate effector caspase-3/9 to trigger cell apoptosis.