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

Abstract

SOD mimics with varying coligand are momentous in developing potential chemotherapeutic drugs. Cu(II) based SOD mimics 1–4 [CuLH(OAc)(H2O)Y)] (LH = 2-((E)-(1,3-dihydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol, OAc = CH3COO, 1: Y = H2O; 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.