Efficient and Selective Extraction of Prenylated Flavonoids from Sophora flavescens Using Ultrasound-Assisted Hydrophobic Ionic Liquid and Characterization of Extraction Mechanism

As a secondary metabolite with vigorous pharmacological activity (antitumor), prenylated flavonoids in Sophora flavescens (PFS) have great potential to be transformed into lead compounds. Its extraction has attracted more and more attention. Conventional organic solutions cannot selectively extract PFS and then need to carry out liquid-liquid extraction and multi-step column separation, which is time-consuming and pollutes the environment. This study found that [C₈mim]BF₄ had a high efficiency and selectivity for extracting PFS. Under the optimal extraction parameters, the yield of PFS was 7.38 mg/g. Based on UHPLC-Q-Orbitrap MS, 39 prenylated flavonoids were identified in PFS freeze-dried powder, which showed strong anti-tumor activity. In addition, the potential mechanism of selective extraction was analyzed in depth. [C₈mim]BF₄ synergy ultrasound destroys the cell wall structure, making the active components in the cell more easily exposed to the extraction solvent. The formation of more hydrogen bonds and van der Waals forces between [C₈mim]BF₄ and PFS accelerates the dissolution of PFS.