A sonochemical strategy integrating enzymatic conversion and purification for efficient production of secondary flavonoid glycosides from Epimedium

This study aimed to developed an integrated ultrasound-assisted approach that incorporates ultrasound into both the enzymatic biotransformation and resin-based purification steps for the efficient preparation of secondary flavonoid glycosides (SFGs) from Epimedium. Ultrasound pretreatment was first applied to cellulase to enhance the deglycosylation of parent flavonoid glycosides (PFGs), followed by ultrasound-assisted purification using ADS-17 resin, while kinetic modeling, adsorption-desorption profiling, and morphological examinations were conducted to elucidate the underlying mechanisms of ultrasonic intensification. Kinetic analysis showed that ultrasonic pretreatment (50 W) significantly accelerated the enzymatic reaction, increasing the first-order rate constant (k₁ from 0.0129 to 0.0287 min^-1) and reducing the time to 99 % conversion (t₉₉) from 356 to 161 min. During purification, pseudo-second-order kinetic modeling confirmed that ultrasound (150 W) enhanced adsorption by increasing the rate constant and raising the equilibrium capacity from 77.58 to 99.06 mg/g, while pseudo-first-order modeling described the accelerated desorption process, in which t₉₅ was shortened by ∼ 40 %. The purified SFGs achieved > 80 % purity as verified by UPLC-Q-TOF-MS. In ovariectomized rats, ultrasound-prepared SFGs markedly improved trabecular microarchitecture, biochemical markers, and OPG/RANKL/RANK signaling, exhibiting superior anti-osteoporotic efficacy compared with crude PFGs. Overall, this work develops a dual-stage ultrasound-intensified strategy that integrates biotransformation with resin purification, providing a green, efficient, and scalable approach for producing high-value natural flavonoids.