title: Inclusion complexes of quercetin with three β-cyclodextrins derivatives at physiological pH: spectroscopic study and antioxidant activity.
abstract: Properties of the inclusion complexes of quercetin (QUE) with sulfobutyl ether-β-cyclodextrin (SBE-β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and methylated-β-cyclodextrin (M-β-CD) in tris-HCl buffer solutions of pH 7.40 were investigated. The stoichiometry and thermodynamic parameters for the complexation process (stability constants K, Gibbs free energy change ΔG, enthalpy change ΔH and entropy change ΔS) were determined using phase-solubility and fluorescence spectra analysis. The thermodynamic studies indicated that the inclusion reactions between QUE and the three β-CDs are enthalpy-driven processes. Proton nuclear magnetic resonance spectroscopy indicated that B-ring, C-ring, and part of A-ring of QUE interact with the cavity of β-CDs. The antioxidant activity of QUE and its inclusion complexes were determined by the scavenging of stable radical DPPH(*). The results showed that the complexed QUE/CDs were more effective than free QUE, with the QUE/SBE-β-CD complex as the best form.
authors.affiliation: School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China. panpanliumin@163.com
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Lina
authors.initials: L
authors.lastname: Dong
authors.forename: Aiju
authors.initials: A
authors.lastname: Chen
authors.forename: Yan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Dezhi
authors.initials: D
authors.lastname: Sun
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Bingquan
authors.initials: B
authors.lastname: Wang
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D017666:Deuterium Oxide / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D017711:Nonlinear Dynamics; D011522:Protons; D011794:Quercetin / Q000737:chemistry*; D012995:Solubility; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D011522:Protons; D012996:Solutions; D047392:beta-Cyclodextrins; D011794:Quercetin; D017666:Deuterium Oxide; D004121:Dimethyl Sulfoxide
keywords: Antioxidant activity; Fluorescence spectra; NMR; Phase-solubility; Quercetin; β-Cyclodextrin