Study of the Interaction between Trans-resveratrol and BSA by the Multi-spectroscopic Method

The interaction of trans-resveratrol and BSA was investigated by means of fluorescence quenching, resonance light scattering, ultraviolet spectroscopy and Fourier Transform Infrared Spectroscopy. Binding of trans-resveratrol to BSA quenches the BSA fluorescence and both static and dynamic quenching occur with complex formation. The apparent binding constants of trans-resveratrol and BSA at 20, 30 and 40 degrees C are 1.95 x 10(6), 1.70 x 10(6) and 1.65 x 106 L.mol(-1), respectively. The binding site values are (1.25 +/- 0.02). According to the Forster theory of non-radiation energy transfer, the binding distances between trans-resveratrol and BSA are 3.47, 3.73 and 3.99 nm at 20, 30 and 40 degrees C, respectively. The negative enthalpy change and positive entropy change indicated that the interaction of trans-resveratrol and BSA was driven mainly by electrostatic forces. The process of binding was spontaneous whereby the Gibbs energy change was negative.