A copper(Ⅱ)-hesperetin complex formulated as [Cu(L)2(H2O)2]·H2O ("L" represented the ligand hesperetin) was synthesized using a novel ion-exchanging resin column method, based on the integration of the separation of hesperetin on hesperetin-loaded resins and the reaction of hesperetin with Cu2+ using CuCl2 as an eluent and reacting reagent. The feasibility of this new method was testified firstly. Results indicated the D296 macroporous strong basic anion exchange resin could effectively adsorb hesperetin and the saturated adsorption capacity was 143.5 mg per mL resin. The favorable concentration of CuCl2 was 0.4 mol/L for the elution and the coordination process of hesperetin. The characterization of the copper(Ⅱ) complex was done by theoretical quantum chemical calculation, elemental and thermal analyses, UV-Vis absorption spectra, FTIR spectra and XRD analysis, results testified that the 4-carbonyl group and 5-hydroxyl group of hesperetin were involved in the coordination reaction. The comparison between hesperetin and its copper(Ⅱ) complex about their bioactivities like the inhibitory effect of α-amylase, antioxidant activities and solubility were evaluated. Results showed the bioactivities of the copper(Ⅱ) complex was better than that of hesperetin.

Huan Wang, Boru Chen and Siming Zhu