DNA/BSA binding ability and genotoxic effect of mono- and binuclear copper (II) complexes containing a Schiff base derived from salicylaldehyde and D, L-glutamic acid

This study examined a two of Cu(II) complexes containing Schiff bases [Cu(salglu)Meim] (1) and [Cu(et)2(im)4][Cu2(salglu)2(im)2] (2), where salglu = (N-salicylidene-D,L-glutamato)2- Meim = 2-methylimidazole, im = imidazole and et = ethanol. The interactions and binding characteristics of the complexes with calf thymus DNA (ctDNA) and bovine serum albumin (BSA) were investigated using UV–Vis and fluorescence spectroscopy. The binding constants K were calculated from the UV–Vis spectroscopic titration results using the McGhee and Hippel equation, and were found to be K = 8.9 (for 1) and 3.1 × 103 M−1 (for 2) in the case of complex-DNA interactions, while Stern-Volmer quenching results were used to determine the values K = 2.74 × 105 and 2.54 × 106 M−1 (for 1 and 2, respectively) in the case of complex-BSA binding. DNA strand breaks in cellular DNA were investigated using single cell gel electrophoresis (comet assay). MCF-7 cancer cell lines and healthy HEK-293T cell lines were exposed to complexes 1 and 2 at a concentration range of 0.001–100 × 10−6 M for 24 h. Complexes 1 and 2 induced significant DNA damage in MCF-7 cancer cell lines, while healthy HEK-293T cell lines were more resistant against their effect.