Interaction between Chrysin-8-sulfonates with Bovine Serum Albumin

Two chrysin-8-sulfonates (i.e., sodium chrysin-8-sulfonate and calcium chrysin-8-sulfonate) were synthesized, and mechanism of the interaction between two chrysin-8-sulfonates and bovine serum albumin (BSA) was studied by fluorospectrometry. Significant quenching of fluorescence of BSA was found by its reaction with two chrysin-8-sulfonates. As judged from the fluorescence quenching constants obtained by Stern-Volmer equation, fluorescence quenching of BSA by chrysin-8-sulfonates was attributed to static quenching. The binding constants, number of binding sites and binding distance were found by applying the equation of site-binding model and Frster′s nonradiative energy transfer theory. Values of thermodynamic parameters ΔH and ΔS were calculated and based on these results, the binding force between sodium chrysin-8-sulfonate and BSA was recognized to be electrostatic attraction, and the binding force between calcium chrysin-8-sulfonate and BSA was hydrogen bond and Vander Waals force.