Spectroscopic studies on the interaction of β-cyclodextrin-8-Hydroxyquiuoline inclusion complex with herring sperm DNA

In this paper the interaction mechanism between β-cyclodextrin-8-Hydroxyquiuoline complex and DNA was studied through spectrometry and thermodynamic methods, as well as viscosity measurements. All of the studies were carried out under the condition of pH 7.4, which is maintained by Tris–HCl buffer solution. From the experimental we know that the β-cyclodextrin-8-Hydroxyquiuoline inclusion complex has a 1:1 stoichiometry. From the result of probe experiment, we found that β-cyclodextrin-8-Hydroxyquiuoline complex could compete with EB for intercalates into DNA thus changing their molecular configuration. The binding constants between β-cyclodextrin-8-Hydroxyquiuoline and DNA are K 300.15 K Θ = 4.225 × 10 5 L / mol, K 310.15 K Θ = 4.057 × 10 5 L / mol , and the corresponding thermodynamic parameters are Δ r H m Θ = 3.14 × 10 3 J / mol , Δ r G m 300.15 K Θ = - 3.23 × 10 4 J / mol , Δ r S m Θ = 97.2 J / ( mol K ) . The further experiment results suggested that there exist electrostatic interaction besides partial intercalation binding.