Influence of DMβCD on the Interaction of Copper(II) Complex of 6-Hydroxychromone-3-carbaldehyde-3-hydroxybenzoylhydrazine with DNA.

The interaction mechanism between a scarcely soluble copper(II) complex of Cu(II)-6-hydroxychromone-3-carbaldehyde-(3'-hydroxy)benzoylhydrazone () in aqueous solution and its DMβCD complex was studied in the presence of DNA through spectroscopy and thermodynamic methods. The thermodynamic results indicate that the binding process of the -DMβCD inclusion complex is a spontaneous process and the inclusion is enthalpy-driven. The binding constants of and -DMβCD with DNA are 2.69 × 10 and 14.7 × 10 L mol, respectively. The stoichiometry of the complex is 1:1, and the determined thermodynamic indicates that the process of binding is spontaneous and entropy-driven. A competitive binding titration with ethidium bromide revealed that efficiently displaces EB from the EB-DNA system. In addition to the thermal denaturation experiments and docking studies, we can confirm that the mode of binding of this complex to DNA is intercalation mode. The presence of DMβCD enhances the aqueous solubility of ; nevertheless, the cyclodextrin did not affect the interaction of with DNA because the inclusion complex breaks down when it binds with DNA.