Microwave-assisted acidic amino acid ionic liquid extraction of isoorientin and isovitexin from Thlaspi arvense L. leaves: Process optimization and method validation

In this study, a microwave-assisted acidic amino acid ionic liquid extraction (MA-AAILE) method was developed for extracting isoorientin and isovitexin from Thlaspi arvense L. leaves. Eight acidic amino acid ionic liquids were synthesized and screened, and phenylalanine-based ionic liquid ([Phe][HSO 4 ]) was selected as the extraction solvent. The extraction process was optimized by single-factor experiments and Box–Behnken response surface methodology. Under the adjusted optimal conditions, namely an ionic liquid dosage of 8%, a liquid-to-solid ratio of 28 mL/g, a microwave power of 540 W, and an extraction time of 25 min, the yields of isoorientin and isovitexin reached 0.88 ± 0.03 mg/g and 3.27 ± 0.07 mg/g, respectively. Method validation confirmed satisfactory stability, precision, and recovery. Compared with the heat reflux method, MA-AAILE achieved comparable or higher extraction efficiency within a shorter extraction time and with lower electricity consumption. A PSO-SVR model was additionally examined as an exploratory supplementary modeling approach based on the BBD dataset, but the extraction optimization was primarily based on RSM and experimental validation. Preliminary molecular dynamics observations suggested possible hydrogen-bonding and aromatic interactions between [Phe][HSO 4 ] and the target flavonoids, which may help explain the extraction behavior but should not be regarded as definitive mechanistic evidence. Molecular dynamics simulations indicated that [Phe][HSO 4 ] enriched and stabilized the target flavonoids through interactions. These results suggest that MA-AAILE is a promising extraction strategy for recovering C-glycosyl flavonoids from T. arvense L. leaves.