Efficient extraction of major catechins in Camellia sinensis leaves using green choline chloride-based deep eutectic solvents

In this study, an efficient microwave-assisted extraction (MAE) method using green deep eutectic solvents (DESs) was developed for the extraction of the major catechins in Camellia sinensis leaves. A series of choline chloride-based DESs were prepared, and DES-4, which was composed of choline chloride and lactic acid, was observed to possess the best extraction performance for the target catechins. Moreover, the main factors affecting the extraction efficiency were optimized using Box–Behnken design (BBD) combined with response surface methodology (RSM), and the optimal conditions were as follows: temperature 66 °C, duration 8 min and solvent/material ratio of 35 mL g−1. Under these conditions, a total extraction yield of 153.7 ± 5.2 mg g−1 was obtained. In addition, the separation of the target catechins from DES-based extraction solution was performed using AB-8 macroporous resin with recovery yields from 75.2% to 86.1%. The present study provided fundamental data for the development of DES-based extraction methods in food and pharmaceutical fields.