Inclusion Of The Cyclodextrin Derivatives On Quercetin

As one of dietary flavonoids,quercetin possesses many bioactivities,such as anti-bacterial,anti-inflammatory,anti-cancer,antioxidant,neuroprotection and hepatoprotective activities and so on.However,its low solubility in water has become a barrier to the application of quercetin in pharmaceutical and food industry.Therefore,it is very necessary to improve the aqueous solubility and bioavailability of quercetin,which is significant for the wide application of quercetin.Cyclodextrins(CDs)are a class of cyclic oligosaccharides composed of(?-1,4)-linked-glucopyranose units.Owing to a hydrophilic outer surface and an inner hydrophobic cavity,CDs can improve the aqueous solubility,stability and bioavailability of some guest molecules by forming the inclusion complexes with them,which can prompt the application of these guest molecules.In this paper,the inclusion of some cyclodextrin derivatives on quercetin was systematically investigated.The research contents and obtained results were as following:(1)The inclusion efficiency of native cyclodextrins(?-,?-and ?-CD)on quercetin was compared by using the phase-solubility method.The results showed that ?-cyclodextrin exhibited the best inclusion capacity.In view of the high cost of ?-CD,?-CD was selected to form the complex with quercetin.And the physicochemical properties of the complex of ?-CD and quercetin were characterized by using ultraviolet-visible spectroscopy(UV),Fourier transform infrared spectroscopy(FT-IR)and X-ray diffractometry(XRD).(2)The inclusion abilities of the ether derivatives of ?-CD(2-hydroxypropyl-?-cyclodextrin,2-hydroxyethyl-?-cyclodextrin and methyl-?-cyclodextrin)on quercetin were investigated by the phase-solubility method.And the best performance was found by methyl-?-cyclodextrin.Then,the inclusion interaction between methyl-?-cyclodextrin and quercetin was studied by using UV,FT-IR,XRD,scanning electron microscopy(SEM)and differential scanning calorimetry(DSC).(3)The inclusion efficiency of two branched CDs(glucosyl-?-cyclodextrin and maltosyl-?-cyclodextrin)on quercetin was measured by the phase-solubility method.The results suggested that the complexing ability of glucosyl-?-cyclodextrin was superior to that of maltosyl-?-cyclodextrin.Then,the complex of glucosyl-?-cyclodextrin and quercetin was prepared and characterized by UV,FT-IR,XRD,SEM and DSC.Its supermolecular structure was obtained by using the molecular docking method.(4)Based on the results of high performance liquid chromatography(HPLC)and thermogravimetric measurement(TG),the aqueous solubility and heat stability of quercetin could be significantly improved by complexing with methyl-?-cyclodextrin and glucosyl-?-cyclodextrin.