Spectroscopic analysis on the resveratrol-DNA binding interactions at physiological pH.

The interaction of resveratrol with calf thymus deoxyribonucleic acid (ctDNA) under physiological conditions (Tris-HCl buffer solutions, pH 7.4) was studied by spectroscopy, fluorescence spectroscopy and viscosity measurement method, respectively. Results indicated that a complex of resveratrol with ctDNA was formed with a binding constant of K(17°C) = 5.49×10(3) L mol(-1) and K(37°C) = 1.90×10(4) L mol(-1). The fluorescence quenching mechanism of acridine orange (AO)-ctDNA by resveratrol was shown to be a static quenching type. The thermodynamic parameters of the complex were calculated by a double reciprocal method: Δ(r)H(m)(s) = 4.64×10(4) J mol(-1), Δ(r)S(m)(s) = 231.8 J K(-1) mol(-1) and Δ(r)G(m)(s) = -2.54×10(4) J mol(-1) (37°C). Spectroscopic techniques together with viscosity determination provided evidences of intercalation mode of binding for the interaction between resveratrol and ctDNA.