Cyclodextrins as resveratrol carrier system

The formation of resveratrol–cyclodextrin inclusion complexes in aqueous solutions has been characterized using the hydroperoxidase activity of lipoxygenase as the enzymatic system. The addition of cyclodextrins to the reaction medium had an inhibitory effect on resveratrol oxidation by lipoxygenase due to the complexation of phytoalexin into the cyclodextrin cavity, which is in equilibrium with free cyclodextrins and free resveratrol, the only effective substrate for lipoxygenase. This inhibitory effect depends on the complexation constant Kc between resveratrol and the type of cyclodextrins used. In the present work β- and G2-β-cyclodextrins were used and their Kc were calculated by nonlinear regression of the inhibition curves obtained in the presence of cyclodextrins. The values obtained were 4317 and 5130 M−1 for β- and G2-β-cyclodextrin, respectively, values which were checked and confirmed by the “cyclodextrin assay”.