Abstract:In this study, the possibility of quercetin (QUE), resveratrol (RES) and caffeic acid phenethyl ester (CAPE) binding simultaneously to BSA was analyzed using protein intrinsic fluorescence quenching, the binding sites of bioactive compounds to BSA was conducted by sites markers and molecular docking, the protective effect of BSA-ligand complexes on bioactive compounds was studied by photostability experiments. It was found that BSA could bind two or three ligands simultaneous to form BSA-ligands complexes and the affinity was affected by the sequence of adding ligands. A protein-triligand complex could be better formed in the order of QUE/RES/CAPE. Molecular docking and site Marker experiments identified RES binding to Sudlow's sites I sites, QUE partially to Sudlow's sites II sites, and the binding sites to hydrophobic cavities between IA and IIA. Complex formation improves the stability of free polyphenols, and the two-ligand and three-ligand complexes protect QUE/RES/CAPE better than single-ligand complexes.