The In Vitro and In Vivo Antioxidant Capacities of Auricularia auricula-judae (Agaricomycetes) Polysaccharides Prepared via Free Radical-Mediated Methods

As a basidiomycete fungus, the cell wall of the Auricularia auricula-judae fruiting body is extremely tough and complex, making it difficult to extract the polysaccharides. In this study, A. auricula-judae crude polysaccharides were extracted by breaking the cell wall with free radicals generated by H2O2-Vc, followed by alcohol precipitation and deproteinization using the Sevag method. The in vitro free radical scavenging capacities against active nitrogen (ABTS and DPPH) and active oxygen (hydroxyl and PTIO) were first studied. Subsequently, a high-fat diet (HFD)-induced obesity model in C57BL/6 mice was established to investigate the effects of A. auricula-judae polysaccharides on the antioxidant capacity of obese mice. The results showed that the A. auricula-judae polysaccharides exhibit concentration-dependent scavenging capacities against active nitrogen (ABTS and DPPH) and active oxygen (hydroxyl and PTIO) radicals, with IC50 values of 0.378 and 0.037 mg/mL for ABTS and DPPH radicals, respectively, and an IC50 value of 0.986 mg/mL for hydroxyl radicals. After being fed a HFD, the mice exhibited significant weight gain and symptoms of oxidative stress injury. A. auricula-judae polysaccharides intervention significantly enhanced the activity of SOD and the level of GSH, reduced MDA content in the liver of the mice (P < 0.05), and alleviated mitochondrial structural damage in the liver. These findings indicate that A. auricula-judae polysaccharides prepared using H2O2-Vc as a solvent can improve the body's antioxidant defense system.