Microwave-assisted Deep Eutectic Solvent Extraction of Xinjiang Wild Prunus cerasifera Ehrh. Polysaccharides and Analysis of Its Antioxidant and Antibacterial Activities

In this study, the optimal process for extracting polysaccharides from wild Prunus cerasifera Ehrh. sourced from Xinjiang was determined, and their antioxidant and antibacterial activities were analyzed. Prunus cerasifera Ehrh. obtained from Daxigou, Huocheng County, Xinjiang, was used as raw materials, polysaccharides were extracted through a microwave-assisted deep eutectic solvent method. The optimal extraction parameters were established via single-factor experiments and response surface methodology optimization, included degreasing, decolorization, and protein removal. Crude polysaccharide extract (PCE) was obtained, whose efficacy was subsequently evaluated through in vitro antioxidant and antibacterial assays. The results revealed that the highest yield of PCE (26.38%±0.73%) was obtained under the following conditions: A malic acid to choline chloride molar ratio of 4:1, microwave power, temperature, and duration of 400 W, 60 ℃, and 70 min, a liquid-to-material ratio of 30:1 (mL/g), and a deep eutectic solvent concentration of 50%. The IC50 values for PCE in scavenging DPPH, ABTS+, and hydroxyl free radicals were 1.163, 0.506, and 2.958 mg/mL, respectively. At a mass concentration of 4 mg/mL, PCE exhibited a total reducing capacity of 0.667. Furthermore, the PCE had significant inhibitory effects against Candida albicans, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa at a mass concentration of 200 mg/mL, with average inhibition zone diameters of 23.45±1.88, 16.12±0.47, 17.68±1.32, 17.20±1.18, and 12.00±0.72 mm, respectively. These findings indicate the promising in vitro antioxidant and antibacterial properties of cherry plum polysaccharides and provide a theoretical foundation for their development and utilization as functional products.