The Binding Ability and Inclusion complexation Behavior of Curcumin with Natural α—，β—，γ—Cyclodextrins and Organoselenium—Bridged Bis（β—cyclodextrin）s

Aim：To investigate quantitatively the binding ability and inclusion complexation behavior of curcumin with natural α-，β-，γ-cyclodextrins(1-3) and a series of organoselenium-bridged bit(β-cyclodextrin)s with simple spacer (4-6).Methods:The spectrophotometric titrations have been performed in KCl-HCl buffer solutioln(pH=2.0) at 25℃ to calculate the complex stability constants(Ks) and Gibbs free energy changes(ΔG°) for the stoichiometric 1:1 incluon complexation of 1-6 with curcumin.Results:The binding ability of β-cyclodextrin for inclusion complexation with guest curcumin is higher than that of α-and γ-cyclodextrinms.As compared with parent β-cyclodextrin for inclusion complexation with guest curcumin is higher than that of α-and γ-cyclodextrins.As compared with parent β-cyclodextrin by a factor 2.8-17.1,Conclusion:Size/shape fit and hydrophobic interaction between host cyclodextrins and guest curcumin molecule are the important factors affecting the binding ability and inclusion complex ation behavior of these cyclodextrins 1-6.