Total Flavonoid Extraction from Baihao Yinzhen Utilizing Ultrasound-Assisted Deep Eutectic Solvent: Optimization of Conditions, Anti-Inflammatory, and Molecular Docking Analysis

Abstract

Background: Despite extensive phytochemical research on white tea varieties, flavonoid profiling in Baihao Yinzhen remains scarce. The development of green and efficient extraction methods is essential to facilitate its potential application in cosmetic formulations. Methods: A deep eutectic solvent-based ultrasound-assisted extraction (DES-UAE) was developed for Baihao Yinzhen flavonoids. After screening of 14 DESs and optimizing the conditions via single-factor and response surface methodology, the extracts were analyzed by UPLC-MS. Anti-inflammatory activity was assessed in LPS-induced RAW264.7 cells by measuring TNF-α and IL-6 levels, with molecular docking simulating flavonoid–cytokine interactions; Results: Among 14 tested deep eutectic solvents, hydroxypropyl-β-cyclodextrin/lactic acid (HP-β-CD/La) was identified as the most effective solvent for flavonoid extraction. Under optimized conditions (HBD/HBA mass ratio 3:1, temperature 60 °C, water content 40%, solid–liquid ratio 1:19, extraction time 62 min), the maximum flavonoid yield reached 108.72 mg RE/g DW. The DES extract (2.5 μg/mL) significantly suppressed TNF-α and IL-6 secretion in LPS-stimulated RAW264.7 cells compared to the water extract. UPLC-MS identified five major flavonoid glycosides, and molecular docking revealed their strong binding affinities with TNF-α and IL-6 proteins. Conclusions: DES-UAE provides an efficient green method for flavonoid extraction. The extract demonstrates significant anti-inflammatory activity, supporting its potential as a natural cosmetic ingredient. This study aimed to develop an efficient and green DES-UAE method for the extraction of flavonoids from Baihao Yinzhen, in order to evaluate the antioxidant and anti-inflammatory activities of the extract and to explore the potential interaction mechanisms of key flavonoids with inflammatory targets via molecular docking.