Characterization and Antioxidant Activity of Quercetin/Methyl-β-Cyclodextrin Complexes

Quercetin (Qu), a polyphenolic flavonoid, is one of the most effective plant originated antioxidants. Despite the potential use of Qu in clinical trials, low water solubility, stability problems and the scarcity of cellular bioavailability limit its applications. The purpose of this study was to enhance aqueous solubility, dissolution rate and antioxidant activity of Qu by complexation with Methyl-β- cyclodextrin (M-β-CD). Analyses results showed that the aqueous solubility, dissolution rate and antioxidant activity of the complex were increased 254-fold, ~3-fold and 10% respectively compared to the pure Qu. Complexes were prepared by freeze-drying and evaporation method. The characteristics of the complexes were evaluated by DSC, XRD, (1)H-NMR, FT-IR, SEM, encapsulation efficacy, in-vitro dissolution rate analyses. Antioxidant activity studies on complexes carried out with DPPH tests. Analyses results showed that the formation of the complexes resulted in enhanced solubility with increased its antioxidant activity of Qu.