Deep Eutectic Solvents Extraction and Optimization of Amentoflavone from Selaginella moellendorffii

To extract the amentoflavone (AME) from Selaginella moellendorffii with deep eutectic solvent technology, three kinds of deep eutectic solvents were prepared by one-step method, and the best deep eutectic solvent for extracting AME of Selaginella moellendorffii was selected. The results of the clear magnetic resonance, fourier infrared spectroscopy and thermogravimetric analysis indicated that the deep eutectic solvent was successfully prepared. The extraction process of AME from Selaginella moellendorffii was optimized by single factors and response surface method. Results showed that, the best deep eutectic solvent was choline chloride:geraniol. The best extraction conditions were molar ratio 1:2, water content 20%, liquid-solid ratio 10 mL/g, ultrasound time 31 min, and the ultrasonic power was 240 W. Under this condition, the actual content of AME was (2.75±0.12) mg/g. The results of comparison with hot immersion method, cold immersion method, ionic liquid ultrasonic extraction method and ethanol ultrasonic extraction method showed that the deep eutectic solvent combined with ultrasonic extraction could not only save the extraction time, but also significantly increase the AME extraction rate.