New cyclometalated iridium(III) complexes bearing substituted 2-(1H-benzimidazol-2-yl)quinoline: Synthesis, characterization, electrochemical and anticancer studies.

New iridium(III) compounds (C-C) bearing 2-(1H-benzimidazol-2-yl)quinoline ligands with different side groups (benzyl, 2,3,4,5,6-pentamethylbenzyl and 2,3,4,5,6-pentafluorobenzyl) were synthesized and characterized by using spectroscopic analyses. The effects of different side groups of iridium compounds on the photophysical and electrochemical properties have been investigated. The cytotoxicity and apoptosis of the compounds have been evaluated on breast cancer cell lines using various methods including MTT assay, flow cytometry, qRT-PCR, and colony formation. The cytotoxicity of C, expressed as IC50 values, was found to be 11.76 μM for MDA-MB-231 and 5.35 μM for MCF-7 cells. For C, the IC50 value was 16.22 μM for MDA-MB-231 and 8.85 μM for MCF-7 cells. In both cell lines, increased levels of Bax and caspase 3, along with downregulation of BCL-2 and positive annexin V staining, were observed, confirming apoptosis. Moreover, the colony-forming abilities in both cell lines decreased after C and C complex treatment. All these results suggest that the compounds C and C may have potential in the treatment of breast cancer, though further research is needed to confirm their efficacy.