Optimized green extraction of flavonoids from Lycium barbarum leaves using betaine-ethylene glycol NADES: Mechanisms, identification, and bioactivity.

The study employed a natural deep eutectic solvent (NADES) to extract flavonoids from Lycium barbarum leaves (LBL) in order to overcome the limitations of conventional solvents. Betaine-ethylene glycol (NADES-11) was identified as the optimal solvent and following process optimisation, the TFC reached 123.94 ± 1.04 mg RE/g (1.92-fold higher than 70% ethanol). FT-IR, SEM and intermolecular interaction calculations revealed that the stable hydrogen-bond network within NADES-11 confers it with high extraction efficiency. The purified extract (PLLF) was identified as containing 21 flavonoid and phenolic compounds, which exhibit potent antioxidant and anti-aging activities through multi-component synergistic effects. NADES-11 maintained a relative extraction rate of over 90% after three cycles, demonstrating excellent environmental sustainability and economic viability. The study provides a sustainable strategy for LBL flavonoid valorization, supporting the potential applications as natural antioxidants and anti-aging agents for functional foods, cosmetics, and pharmaceuticals.