DNA Binding and DNA Cleavage Activities of Newly Synthesized CoII and CuII Complexes of a β-Cyclodextrin Based Azo-Functionalized Schiff Base

Two water soluble complexes with Co-II and Cu-II ions were synthesized using a novel beta-cyclodextrin based azo-functionalized Schiff base as a ligand. The Schiff base and its metal complexes were characterized by different physicochemical and spectroscopic methods. From the analyses of the experimental data, distorted octahedral geometry has been assigned for both the metal complexes. The binding interactions between the metal complexes andDNAwere investigated by means of a thermal denaturation study and viscosity measurements as well as by electronic absorption and fluorescence spectroscopy. The DNA cleavage efficacy of the metal complexes was also studied by agarose gel electrophoresis using pBR DNA. These studies revealed that both the metal complexes followed an intercalative mode of binding to calf thymus (CT)-DNA and also effectively cleaved the supercoiled pBR DNA. The Co-II complex, however, more efficiently cleaved CT-DNA than the Cu-II complex as much as the experimental results are concerned.