DNA binding affinity and antioxidative activity of copper(II) and zinc(II) complexes with a novel hesperetin Schiff base ligand

A hesperetin Schiff base ligand (H₄L) and its complexes, [H₃CuL·OAc]·H₂O and [H₃ZnL·OAc]·2H₂O, have been synthesized and characterized on the basis of elemental analysis, molar conductivity, ¹H NMR, mass spectra, UV-Vis spectra and IR spectra. The binding of these two complexes and the ligand to DNA has been investigated by ultraviolet absorption spectroscopy, fluorescence spectroscopy and viscosity measurements. The experiments indicate that all the compounds can bind to DNA through an intercalative mode and the complexes intercalate into DNA more deeply than that of the ligand. In addition, the antioxidative activity was also determined. The 50% inhibition obtained for the ligand and its complexes demonstrates that, compared to the ligand, the complexes exhibit higher antioxidative activity in the suppression of and HO.