Optimization of Deep Eutectic-like Solvent-based Ultrasound-assisted Extraction of Polysaccharides from Leonurus Residues

Abstract

Effects of the different types of deep eutectic-like solvents (DESs), molar ratio, water content, extraction temperature, extraction time, and ratio of liquid to solid were studied relative to the yield of Leonurus residue crude polysaccharide (LRCP). Extraction amounts of LRCP were determined. The extraction process parameters were optimized by response surface methodology, and an optimal extraction process was achieved. The results showed that DESs comprising choline chloride and ethylene glycol (CCEG) were suitable for the extraction. The optimum extraction process was as follows: water content, 27%; extraction temperature, 62 °C; and extraction time, 48 min. With the abovementioned parameters, the predicted extraction yield of LRCP was 14.1%. It was found that with these optimal extraction conditions, a 52.9% higher extraction yield could be achieved compared with hot water extraction. Therefore, a type of DES was found to be an excellent extraction solvent alternative for the extraction of polysaccharides and has a practical value.