Synthesis, characterization and <i>in vitro</i> DNA binding studies of a new copper(II) complex containing antioxidant ferulic acid

<p>A mononuclear Cu(II) complex, [Cu(FA)<sub>2</sub>(NO<sub>3</sub>)<sub>2</sub>], in which FA is ferulic acid ((E)-3-(4-hydroxy-3-methoxy-phenyl)prop-2-enoic acid), was synthesized and characterized by spectroscopic methods. The main structures of the ligand and its complexes with Cu<sup>2+</sup> were optimized by QM calculations. The calculations on the structures of the [Cu(FA)<sub>2</sub>(NO<sub>3</sub>)<sub>2</sub>] complexes forms and the intercalating with DNA profile were undertaken by UHF/PM6 and MMFF94 methods, respectively. <i>In vitro</i> studies (UV-vis spectroscopy, emission titration, circular dichroism techniques, and viscometry) under physiological conditions (Tris-HCl buffer solutions, pH 7.4) showed that the complex interacts with calf-thymus DNA (ct-DNA) via an intercalative binding mode. The thermodynamic parameters, enthalpy change (ΔH), and entropy change (ΔS) showed that the acting forces between Cu(II) complex and ct-DNA mainly included van der Waals interactions and hydrogen bonds. Methylene blue (MB) displacement studies revealed that Cu(II) complex can substitute MB probe in the MB-DNA complex which was indicative of intercalative binding. The theoretical data confirm the experimental results with respect to the mechanism of binding.</p>