Mixed-ligand Cu(II)-vanillin Schiff base complexes; effect of coligands on their DNA binding, DNA cleavage, SOD mimetic and anticancer activity.

SOD mimics with varying coligand are momentous in developing potential chemotherapeutic drugs. Cu(II) based SOD mimics 1-4 [CuLH(OAc)(H(2)O)Y)] (LH = 2-((E)-(1,3-dihydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol, OAc = CH(3)COO, 1: Y = H(2)O; 2: Y = phen (1,10-phenanthroline), 3: Y = tpimH (2,4,5-triphenylimidazole); 4: Y = tfbimH (2-(trifluoromethyl)benzimidazole) were synthesized and thoroughly characterized. Their interaction with CT-DNA showed different non-covalent binding behaviour. SOD activity of 2 was highest among 1-4 which was further validated by gel electrophoresis. The pBR322 plasmid strand break offered by 2 + O₂·⁻ system reveals oxidative cleavage mechanism. In vitro antimicrobial activity of 1-4 was shown by percent inhibition data while in vitro anticancer activity of 1-4 was screened using 16 human carcinoma cell lines of different histological origin. Complex 2 showed higher efficacy towards 14 cell lines.