Synthesis, Structure, DNA/BSA Binding, DNA Cleaving, Cytotoxic and SOD Mimetic Activities of Copper(II) Complexes Derived from Methoxybenzylamine Schiff Base Ligands.

Schiff base ligands prepared from salicylaldehyde and 2-, 3- and 4-methoxybenzylamine were used to prepare copper(II) complexes, characterized by spectral methods, elemental analysis and X-ray crystallography in the case of complex derived from 2-methoxybenzylamine. The DNA cleavage activity of the prepared complexes was exceptional, with best activities of over 95% one-strand cleavage for at 3 mM and full double-strand cleavage for complex at 5 mM. Absorption titration studies with ct-DNA revealed good binding constants (at 10 M) with a decrease of up to 56% light absorption. Meanwhile, the EB-DNA displacement method and viscosity studies revealed groove binding as a possible binding mode. For BSA binding studies, all three complexes showed K values in the optimal range for reversible BSA binding (10 M). The copper(II) complexes showed significant cytotoxic effects (67-96% at 1 mM) in mitochondrial activity monitoring assays. Cytotoxicity was confirmed against cancer cell lines (A549 and HepG2) and HEL cells. The complexes and exhibited high activity against HepG2 cancer cells (IC50 < 22 μM), comparable to cisplatin. The radical scavenging activity was determined by the INT method with the best IC50 for (189 ± 11 μM). Overall, complexes and with a methoxy group in the and positions show high potential in most determined activities, but mainly as DNA cleavers and as cytotoxic agents with selectivity against HepG2 cells.