Polypyridyl CoII‐Curcumin Complexes as Photoactivated Anticancer and Antibacterial Agents

Abstract

AbstractFour new CoIIcomplexes, [Co(bpy)2(acac)]Cl (1), [Co(phen)2(acac)]Cl (2), [Co(bpy)2(cur)]Cl (3), [Co(phen)2(cur)]Cl (4), where bpy=2,2’‐bipyridine (1and3), phen=1,10‐phenanthroline (2and4), acac=acetylacetonate (1and2), cur=curcumin monoanion (3and4) have been designed, synthesized and fully characterized. The X‐ray crystal structures of1and2indicated that the CoN4O2core has a distorted octahedral geometry. The photoactivity of these complexes was tuned by varying the π conjugation in the ligands. Curcumin complexes3and4had an intense absorption band near 435 nm, which made them useful as visible‐light photodynamic therapy agents; they also showed fluorescence withλem≈565 nm. This fluorescence was useful for studying their intracellular uptake and localization in MCF‐7 breast cancer cells. The acetylacetonate complexes (1and2) were used as control complexes to understand the role of curcumin. The white‐light‐triggered anticancer profiles of the cytosol targeting complexes3and4were investigated in detail. These non‐dark toxic complexes displayed significant apoptotic photo‐cytotoxicity (under visible light) against MCF‐7 cells through ROS generation. The control complexes1and2did not induce significant cell death in the light or dark. Interestingly,1‐4produced a remarkable antibacterial response upon light exposure. Overall, the reported results here can increase the boundary of the CoII‐based anticancer and antibacterial drug development.