Cyclometallated iridium(III)-5-bromo-8-quinolinol complexes as mitochondria-targeted anticancer agents

Here, two new cyclometallated iridium(III) complexes, [Ir(BrQ)(L1)(2)] (Ir-1) and [Ir(BrQ)(L2)(2)] (Ir-2) containing 5-bromo-8-quinolinol (H-BrQ), 2-phenylpyridine (H-L1) and 1-phenylpyrazole (H-L2) ligands have been explored as an anticancer agents targeting mitochondria. The cyclometallated iridium(III) complexes Ir-1 and Ir-2 exhibits excellent antineoplastic activity and promising selectivity towards cervical carcinoma HeLa, with IC50, values were 3.53 +/- 0.44 mu M and 0.50 +/- 0.39 mu M, as compared to the human HL-7702 healthy cells and cisplatin-resistant SK-OV-3/DDP cancer cells. Flow cytometry confirmed that cervical carcinoma HeLa cells were caused apoptosis after being treatment with Ir-1 and Ir-2. Along with the decrease of mitochondrial membrane potential (MMP) level, massive release of cytochrome c (cyto C), clear changes in apoptosis-associated proteins, and triggers caspase-mediated mitochondrial dysfunction apoptosis pathways.