Characterization of the baicalein-bovine serum albumin complex without or with Cu2+ or Fe3+ by spectroscopic approaches

The binding of baicalein to bovine serum albumin (BSA) in the absence and presence of Cu2+ or Fe3+ in aqueous solution has been studied by fluorescence, synchronous fluorescence, ultraviolet visible (UV-vis) spectra, circular dichroism (CD) and the three-dimensional (3D) fluorescence at pH 7.40. The decrease of the binding constant in the presence of Cu2+ or Fe3+ may result from the competition of the metal ions and baicalein binding to BSA. The effect of baicalein on the conformation of BSA was analyzed using UV. CD, fluorescence and three-dimensional (3D) fluorescence. These results indicate that the binding of baicalein to BSA causes apparent change in the secondary structure of BSA, but does not affect the polarity around the chromophore molecule. (C) 2010 Published by Elsevier Masson SAS.