Low-temperature ultrasonic-deep eutectic solvent extraction of ergothioneine from Pleurotus ostreatus: A sustainable new strategy.

Ergothioneine (EGT) is a potent antioxidant. This study employed a low-temperature ultrasonic-assisted deep eutectic solvent (UA-DES) method for the efficient and sustainable extraction of EGT from Pleurotus ostreatus mushrooms. Conductor-like screening model for real solvents (COSMO-RS) guided screening of the optimized choline chloride (CC)-citric acid (CA) system contented 3.22 mg/g DW of EGT-substantially higher than that obtained using traditional solvents such as 70% ethanol (1.05 mg/g DW-which increased to 11.39 ± 0.57 mg/g DW under optimal experimental conditions. EGT separation and recycling with LX-1085H resin contented a crude product with 69.25% purity, while the CC-CA system was reusable for more than four cycles. Kinetic studies indicated that UA-CC-CA enhances extraction through high mass transfer, robust hydrogen bonding, and ultrasound-induced cell disruption. Low temperatures preserved antioxidant activity, and the method required less energy and produced minimal CO2 emissions. Thus, UA-CC-CA offers a scalable, eco-friendly approach for extracting natural products.