[Study on the interactions of genisten esterified derivatives with bovine serum albumin].

Under the imitated physiological conditions (pH = 7.4), the interactions of two novel genistein esterified derivatives, genistein 7-acetylferulic acid ester and genistein 7, 4'-di-acetylferulic acid ester (1 and 2), with bovine serum albumin (BSA) were investigated by the fluorescence and UV-Vis spectroscopy. It was observed that both of them can effectively quench the intrinsic fluorescence of BSA. The results suggested that the fluorescence quenching process of BSA at low concentrations of the compounds may be mainly governed by static quenching mechanisms. The binding constants (KA) and the number of binding sites (n) at different temperatures were calculated. From the thermodynamic parameters, it can be judged that the binding of 1 to BSA involved electrostatic interactions, whereas the binding of 2 to BSA involved hydrogen bonds and Van der Waals forces. The binding average distances r between BSA (donor) and the compounds (acceptor) were determined to be 2.63 nm and 2.92 nm respectively based on the Forster theory. Besides, the interactions of BSA with the compounds did not change the conformation of BSA and the binding of compounds to BSA is near tryptophan subunit via synchronous fluorescence spectrometry.