Synthesis, characterization, DNA binding and cleavage, HSA interaction and cytotoxicity of a new copper(II) complex derived from 2-(2′-pyridyl)benzothiazole and glycylglycine

A new copper(II) complex, [Cu(glygly)(pbt)(H2O)]ClO4 (glygly = glycylglycine anion and pbt = 2-(2′-pyridyl)benzothiazole) was synthesized and characterized by elemental analysis, molar conductivity, mass spectra, IR spectra, UV–vis spectra and thermogravimetric analysis (TGA). Spectroscopic titration, viscosity, and electrophoresis measurements revealed that the complex intercalated to calf thymus (CT)-DNA with moderate binding affinity (Kb = 5.64 × 104 M−1), and cleaved pBR322 DNA at a low concentration of 5 μM in the presence of ascorbic acid, presumably via an oxidative mechanism. Further, the protein-binding ability has been monitored by various spectroscopic techniques (UV–vis, fluorescence and CD) using human serum albumin (HSA) as a model protein. The complex displayed desired affinity to HSA in which hydrophobic interaction played a major role. In addition, the complex was subjected to cytotoxicity tests in vitro using three human cancer cells lines (HepG2, HeLa and A549) and showed prominent and selective cytotoxicity against HepG2 cell lines (IC50 ∼ 17.78 μM).