Interaction between Fisetin and Cyclodextrins

Fisetin possesses many health-promoting properties,such as antioxidant,anticancer activities.Its poor solubility and stability in water limit its application in medicines,cosmetics and foods.Its shortcomings can be overcome by complexing with cyclodextrins (CDs).But there is no systematic report about its interaction with CDs.In view of this,the effect of ɑ-cyclodextrin (α-CD),β-cyclodextrin (β-CD),γ-cyclodextrin (γ-CD) and maltosyl-β-cyclodextrin (M-β-CD) on the aqueous solubility of fisetin was compared by the phase solubility method.Then,the complex of fisetin and M-β-CD was prepared and characterized by using ultraviolet-visible spectrum (UV),ultraviolet-visible spectrum (IR) and X-ray diffraction (XRD).Based on the experimental results,the three-dimensional supermolecular structures of fisetin/CD complexes was established by using molecular docking method.It was found that the inclusion effects of M-β-CD and β-CD on fisetin were higher than those of α-CD and β-CD.After complexing with M-β-CD,the physicochemical properties of fisetin were significantly changed,which were completely dispersed in M-β-CD.The molecular docking analysis suggested that fisetin entered the hydrophobic cavity from the wide rim of M-β-CD,and the complex was maintained by hydrogen bonding.