Synthesis and evaluation of anticancer properties of novel benzimidazole ligand and their cobalt(II) and zinc(II) complexes against cancer cell lines A-2780 and DU-145

Eighteen new cobalt(II) or zinc(II) complexes of benzimidazole bearing 1-benzyl and 2-phenyl moieties were synthesized from the reaction of appropriate benzimidazole ligands and CoCl2 or ZnCl2. Their structural characterizations were done by IR, NMR (H-1, C-13) and UV-VIS spectrometers. Cytotoxic activities of eighteen new complexes and three benzimidazole ligands were determined using A-2780 (human ovarian) and DU-145 (human prostate) cell lines. Antitumor properties of all compounds were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell viability assay for the tested benzimidazole derivatives was performed and the LogIC(50) values of the compounds were calculated after a 24-hour treatment. All tested benzimidazole derivatives showed higher or comparable antitumor activity against A-2780 cell lines compared to the standard drug docetaxel with a LogIC(50) value of -0.81 mu M (p < 0.05). Eight of the examined compounds (1, 3, 5, 6, 7, 9, 10 and 13) showed high cytotoxic activity against A-2780 compared to the standard drug docetaxel. While the LogIC(50) of the docetaxel was -0.81 mu M for A-2780 cells at 24 h, the IC50 values of compounds 1, 3, 5, 6, 7, 9, 10 and 13 were - 0.97, -1.30, - 0.22, 0.13, - 0.16, - 0.73 and - 0.53 mu M, respectively. Three of the compounds 1, 18 and V showed high cytotoxic activity against DU-145 compared to docetaxel (p < 0.05). While the LogIC(50) of the docetaxel was -1.13 mu M for DU-145 cells at 24 h, the LogIC(50) values of compounds 1, 18 and V were 0.84, -0.38 and -0.66 mu M, respectively.