Fluorescence studies of interaction between flavonol p-coumaroylglucoside tiliroside and bovine serum albumin.

Abstract In this paper, the interaction between flavonol p-coumaroylglucoside tiliroside and BSA was investigated by fluorescence quenching spectra, synchronous fluorescence spectra, and three-dimensional fluorescence spectra under simulative physiological conditions. It was proved that the fluorescence quenching of BSA by tiliroside was mainly a result of the formation of a tiliroside–BSA complex. The modified Stern-Volmer quenching constant and the corresponding thermodynamic parameters Δ H , Δ G and Δ S at different temperatures were calculated. The results indicated that electrostatic interactions were the predominant intermolecular forces in stabilizing the complex. The distance r  = 3.95 nm between the donor (BSA) and acceptor (tiliroside) was obtained according to Forster's nonradioactive energy transfer theory. The synchronous fluorescence and three-dimensional fluorescence spectra results showed the microenvironment and conformation of BSA were changed in the binding reaction.