Effect of Structure and Composition of Copper and Cobalt Complexes with Schiff Base Ligands on their DNA/Protein Interaction and Cytotoxicity

Four transition metal complexes, namely Cu 2 Cl 2 (HL 1 ) 2 ( 1 ), Co(HL 1 ) 2 ( 2 ), Cu(HL 2 ) 2 ( 3 ), Co(HL 2 ) 3 ( 4 ) {H 2 L 1 = 2-{[2-(2-hydroxy-ethoxy)-ethylimino]-methyl}-phenol, H 2 L 2 = 3-{[2-(2-hydroxy-ethoxy)-ethylimino]-methyl}-naphthalen-2-ol} were synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. The interactions of these copper and cobalt complexes with calf thymus DNA (CT-DNA) were studied by absorption and emission titration spectroscopic methods. The interactions of these copper and cobalt complexes with bovine serum albumin (BSA) were also investigated using fluorescence, UV/Vis, and synchronous fluorescence spectroscopy. Further, the in vitro cytotoxic effect of the complexes are examined on human colon carcinoma cell lines (HCT-116) and human lung carcinoma cell line (A549).