A Cu2+-functionalized supramolecular deep eutectic solvent with tunable polarity: synergistic coordination and host-guest inclusion for efficient and selective flavonoid extraction

Triple functions: Cu 2+ coordination, CMCD inclusion and polarity switchable. • Selective for 4‑carbonyl-5-hydroxy flavonoids; baicalin yield 160 mg/g. • Higher extraction yield than conventional methods/organic solvents. • Mechanism clarified by DFT/docking/IGMH. To address the inherent limitations of conventional deep eutectic solvents, such as poor selectivity and tedious separation procedures, this study prepared a novel Cu 2+ -functionalized metal-supramolecular deep eutectic solvent (MSDES) for the efficient and highly selective extraction of flavonoids from Scutellaria baicalensis Georgi. The MSDES integrates three synergistic mechanisms: Cu 2+ coordination for specific molecular recognition, carboxymethyl-β-cyclodextrin host-guest inclusion for enhanced compatibility, and the combination of decanoic acid with N , N -dimethylcyclohexylamine for polarity-switchable phase separation. This design not only improves extraction yield but also simplifies recovery, eliminating the need for distillation. Under the optimized conditions, the extraction yield of baicalin reached 160 mg/g, which was significantly higher than those obtained with conventional DESs and organic solvents. The system was characterized by UV–Vis, 1 H NMR and FT-IR spectroscopies, and the extraction mechanism was elucidated by DFT calculations and molecular docking. This study addresses the critical issue of insufficient molecular recognition precision in conventional DESs, providing an efficient novel strategy for the extraction of bioactive components from traditional Chinese medicinal materials. Download: Download high-res image (179KB) Download: Download full-size image