Spectroscopic Study On The Antioxidant Activity Of Riboflavin In The Presence Of Bilirubin

The present study illustrates the action of different concentrations of bilirubin upon the antioxidant activity of the riboflavin using the chemiluminescent system luminol-hydrogen peroxide, in phosphate buffer, pH 7. It was found that bilirubin decreases the chemiluminescence intensity of the generating system and, as a function of concentration, in the presence of riboflavin, enhances its antioxidant activity. The quenching effect of the bilirubin on the riboflavin fluorescence was found to be solvent dependent. The evidence of the electron donor ability as well as the energy transfer efficiency of the riboflavin to bilirubin has been suggested. Molecular dynamics study evidenced that the minimum value of the binding energy of the riboflavin towards bilirubin is -159.8 kJ/mol.