Optimization of Enzymatic-Assisted Aqueous Two-Phase Extraction Conditions of Polysaccharides from Cordyceps cicadae and Analysis of Its Antioxidant, Hypoglycemic and Hypolipidemic Properties In Vitro

Polysaccharides are one of the main constituents of Cordyceps cicadae (C. cicadae), and they show various biological activities. In the present study, C. cicadae fruiting bodies were used as raw materials to extract polysaccharides using an aqueous two-phase system, along with cellulase and pectinase, aiming to provide references for the further development, utilization, and in-depth research of C. cicadae polysaccharides. Effects of cellulase and pectinase addition amounts and (NH₄)₂SO₄ and polyethylene glycol (PEG) mass fractions on the polysaccharide-extraction rates were analyzed by single-factor experiments. The conditions for C. cicadae polysaccharide extraction were optimized by response-surface methodology, and the antioxidant, hypoglycemic, and hypolipidemic properties of the polysaccharides were evaluated in vitro. The optimal conditions for C. cicadae polysaccharide extraction were as follows: cellulase addition amount, 2.01%, pectinase addition amount, 2.07%, (NH₄)₂SO₄ mass fraction, 17.72%, and PEG mass fraction, 20.87%, the polysaccharide-extraction rate reached 30.05% under these conditions. When the C. cicadae polysaccharide concentration was 1.0~5.0 mg/mL, the maximum Fe²⁺-chelating and ABTS⁺ radical-clearance abilities were 16.33%±1.68% and 17.38%±3.07%, respectively. The determination of total reducing power showed that the maximum absorbance of C. cicadae polysaccharides was 0.53. The maximum inhibitory rates of C. cicadae polysaccharides for α-amylase and α-glucosidase activities were 30.96%±4.53% and 49.40%±1.30%, respectively, the maximum adsorption rates of C. cicadae polysaccharides for sodium cholate, sodium taurocholate, and cholesterol were 47.24%±1.89%, 44.88%±0.82%, and 70.19%±2.54%, respectively. The results indicate that C. cicadae polysaccharides demonstrate effective antioxidant, hypoglycemic, and hypolipidemic abilities in vitro. This study will provide a theoretical basis for developing C. cicadae polysaccharide-related products, especially for clinical applications.