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

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 DeltaH, DeltaG and DeltaS 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 Förster'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.