Binding Interaction Study of β-sitosterol and Luteolin-7-glucoside with Bovine Serum Albumin by Fluorescence Quenching

Abstract

The study on drug-protein interactions is an important field of interest because of the perspective of unraveling of drug action mechanisms and the possibility of designing novel medicines. Bovine serum albumin (BSA) has been studied extensively, because of its structural homology with human serum albumin (HSA). β-Sitosterol is a phytosterol compound that has a variety of pharmacological properties Luteolin 7- glucoside is a glycosyloxy flavones, which has a role as an antioxidant. By fluorescence spectroscopy, this study investigated the interaction between β-sitosterol and Luteolin-7-glucoside with bovine serum albumin (BSA) at physiological pH 7.4. The study revealed that the fluorescence quenching of BSA by molecules resulted from forming a molecule-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer to measure the binding affinity between the molecules and BSA. Thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures indicated that action was an endothermic and spontaneous process, and hydrophobic interaction played a major role in molecule-BSA association.