Purification of flavonoids from buckwheat husk extracted by deep eutectic solvent, and their antioxidant activities

This study investigated the purification conditions of flavonoids from buckwheat husks using six macroporous resin. Their static and dynamic adsorption and desorption characteristics of the crude extract of buckwheat husk flavonoids (BHF), obtained with choline chloride/lactic acid (CC/LA) were evaluated. Results indicated that HPD-500 resin provided the optimal purification performance under the following conditions: sample concentration of 1.5 mg/mL, loading volume of 2 bed volumes (BV), and flow rate of 0.5 mL/min; elution solvent with 70% ethanol at volume of 4 BV and flow rate of 1.0 mL/min. Under these conditions, the purity of BHF increased from 27.95%to 72.40%. UV-Vis and FT-IR spectra analysis confirmed the characteristic peaks and functional groups typical of flavonoids. UPLC-HRMS identification revealed the presence of 11 flavonoid compounds, including rutin, quercitrin, hyperin, luteolin, vitexin, and hesperidin. Compared to the crude extract, the purified BHF demonstrated significantly enhanced antioxidant activities, indicating its potential as natural antioxidant.

The online version contains supplementary material available at 10.1007/s10068-025-02054-z.