title: Structural relationship and binding mechanisms of five flavonoids with bovine serum albumin.
abstract: Flavonoids are structurally diverse and the most ubiquitous groups of dietary polyphenols distributed in various fruits and vegetables. In this study, the interaction between five flavonoids, namely formononetin-7-O-β-D-glucoside, calycosin- 7-O-β-D-glucoside, calycosin, rutin, and quercetin, and bovine serum albumin (BSA) was investigated by fluorescence and UV-vis absorbance spectroscopy. In the discussion, it was proved that the fluorescence quenching of BSA by flavonoids was a result of the formation of a flavonoid-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer and Lineweaver-Burk equations to provide a measure of the binding affinity between the flavonoids and BSA. The binding constants ranked in the order quercetin>rutin>calycosin>calycosin-7-O-β-D-glucoside ≈ formononetin-7-O-β-D-glucoside. The results of thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures indicated that the hydrophobic interaction played a major role in flavonoid-BSA association. The distance r between BSA and acceptor flavonoids was also obtained according to Förster's theory of non-radiative energy transfer.
authors.affiliation: Key Laboratory of Modern Chinese Medicines, China Pharmaceutical University, Ministry of Education, Nanjing 210009, China.
authors.forename: E-Hu
authors.initials: EH
authors.lastname: Liu
authors.forename: Lian-Wen
authors.initials: LW
authors.lastname: Qi
authors.forename: Ping
authors.initials: P
authors.lastname: Li
mesh_terms: D000818:Animals; D002417:Cattle; D005419:Flavonoids / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence / Q000379:methods; D013329:Structure-Activity Relationship
chemical_list: D005419:Flavonoids; D012710:Serum Albumin, Bovine