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PubMed · 15793810

Physicochemical and structural characterization of quercetin-beta-cyclodextrin complexes.

Ying Zheng·Ian S Haworth·Zhong Zuo·Moses S S Chow·Albert H L Chow
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Abstract

Quercetin is a bioactive flavonoid widely used as a health supplement. Being sparingly soluble and chemically unstable in aqueous intestinal fluids, quercetin is poorly absorbed orally. This study aimed to investigate the effects of three beta-cyclodextrins, namely, unsubstituted beta-cyclodextrin (beta-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), and sulfobutyl ether beta-cyclodextrin (SBE-beta-CD) on the chemical stability and water solubility of quercetin, and to elucidate the complexation mechanisms of these beta-CDs with quercetin. Quercetin-beta-CD complexes in solution were characterized by stability assessment, phase solubility measurements, and 1H-nuclear magnetic resonance (NMR) spectroscopy. Molecular modeling was used to help establish the mode of interaction of the beta-CDs with quercetin. Solubility enhancements of quercetin obtained with the three beta-CDs followed the rank order: SBE-beta-CD > HP-beta-CD > beta-CD. The stability of quercetin at alkaline pHs also showed substantial improvement. NMR spectroscopic analysis suggested that the B-ring, C-ring, and part of the A-ring of quercetin display favorable interaction with the hydrophobic cavity of the beta-CDs, which was confirmed by molecular dynamics (MD) simulations using a solvated model of the quercetin-beta-CD complex. An inclusion complex model has been established for explaining the observed augmentation of solubility and stability of quercetin in water by beta-CDs.

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Chemical PhenomenaChemistry, PhysicalChromatography, High Pressure LiquidDrug StabilityHydrogen-Ion ConcentrationIndicators and ReagentsMagnetic Resonance SpectroscopyModels, MolecularQuercetinSolubilitySpectrophotometry, UltravioletThermodynamicsWaterbeta-CyclodextrinsJournal ArticleResearch Support, Non-U.S. Gov't

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Ying Zheng, Ian S Haworth, Zhong Zuo, Moses S S Chow, Albert H L Chow. 2005. Physicochemical and structural characterization of quercetin-beta-cyclodextrin complexes.. https://doi.org/10.1002/jps.20325

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