Deep eutectic solvent-based green extraction and antioxidant evaluation of polyphenols from Malus coronaria crabapple...

Malus coronaria crabapple is a widely cultivated plant worldwide. This study optimized a green extraction process for polyphenols from M. coronaria crabapple fruits (MAPp) using deep eutectic solvents (DES) and evaluated their chemical composition and antioxidant properties. A DES system based on chlorocitrate-acetic acid (1:3) was optimized through single-factor experiments and the Box-Behnken design. Under the optimal conditions (56.9% water content, 46 min extraction time, and 42 °C extraction temperature), the polyphenol yield reached 116.48 ± 0.13 mg GAE·g^-1 DW, significantly exceeding that of traditional solvents. LC-MS analysis was conducted for six polyphenolic compounds: phloridzin, catechin, chlorogenic acid, quercetin, rutin, and gallic acid. Polyphenolic substances were identified by UPLC-Q-TOF-MS/MS. MAPp exhibited strong in vitro antioxidant capacity. Simulated digestion showed partial recovery of antioxidant activity after digestion. Overall, this study provides a green extraction strategy for plant polyphenols and highlights the antioxidant potential of MAPp.