Microwave-Assisted Hydrogen Peroxide Synergistic Extraction of Auricularia auricula-judae (Agaricomycetes) Polysaccharides and Their Antioxidant Stress Response

Oxidative stress, as the core pathological mechanism of imbalance in the body's oxidation-antioxidation system, is a key inducer of accelerated aging and degenerative diseases. This study, based on the synergistic principle of microwave energy and free radicals, constructed a microwave-assisted hydrogen peroxide (H2O2) synergistic system to optimize the extraction yield of Auricularia auricula-judae polysaccharide (AAPs-m) using the Box-Behnken design model based on single-factor experiments. A methyl viologen-induced oxidative stress model of Caenorhabditis elegans was established to evaluate the in vivo antioxidant stress capacity of AAPs-m. The results showed that the AAPs-m yield reached 36.76% ± 0.38% under the conditions of a liquid-to-solid ratio of 60.0 mL/g, a H2O2 concentration of 1.5% a microwave power of 400 W, and a temperature of 100°C for 61 min. AAPs-m is a heteropolysaccharide composed of mannose, glucuronic acid, glucose, galactose, and xylose, with a molar ratio of 53.82:6.10:25.50:2.36:11.44. Among them, the molar ratio of mannose is high, which is rare in AAPs extracted by other methods. AAPs-m significantly prolonged the lifespan of C. elegans under oxidative stress conditions (P < 0.05) and significantly enhanced the antioxidant system, including increasing the activities of superoxide dismutase and catalase, increasing glutathione (GSH) levels, and decreasing malondialdehyde (MDA) content (P < 0.05). In summary, AAPs-m, effectively extracted by microwave-assisted H2O2 synergistic technology, possesses antioxidant stress capabilities and has great potential and development value.