The immuno-regulating potential of edible fungus polysaccharides has gained more and more attention. However, there is little information about the study ofAuricularia corneavar. Li. polysaccharides regulating immunomodulatory activity. The objective of this work to analyze the immunomodulatory activity and the mechanism ofA. corneavar. Li. polysaccharides supplementation in an immunosuppressed mice model induced by cyclophosphamide. The effects ofA. corneavar. Li. polysaccharides on immune system including immune organ indices, immunoglobulin contents, and inflammation cytokines in immunosuppressed mice were determined. In addition, the regulatory effects ofA. corneavar. Li. polysaccharides on the gut microbiota and their metabolites were analyzed. Results showed thatA. corneavar. Li. polysaccharides significantly elevated immune organ indexes, remarkably enhanced the levels of immunoglobulin A (IgA), IgG and IgM in serum and secretory IgA (sIgA) in the intestinal mucosa, conspicuously stimulated the levels of tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), IL-4, and IL-10 in the serum.A. corneavar. Li. polysaccharides also could restore gut microbiota to the pattern that is similar with that of the control group with increase of the relative abundances of short-chain fatty acids (SCFAs)-producing bacteria. Furthermore, the content of SCFAs were increased afterA. corneavar. Li. polysaccharides supplementation. This study provides useful information for applications ofA. corneavar. Li. polysaccharides in immune-regulated foods and medicine.

Edible fungi bioactive peptides (BAPs) are extracted from fruiting bodies and the mycelium of edible fungus. They have various physiological functions such as antioxidant activity, antihypertensive activity, and antibacterial activity. In this paper, the preparation and purification methods of edible fungus BAPs were reviewed, their common biological activities and structure-activity relationships were analyzed, and their application prospects were discussed.

With the acceleration of the pace of life, increased stress levels, and changes in lifestyle factors such as diet and exercise, the incidence of diseases such as cancer and immunodeficiency has been on the rise, which is closely associated with the impaired antioxidant capacity of the body. Polypeptides and polysaccharides derived from edible fungi demonstrate significant strong antioxidant activity and immunomodulatory effects. Auricularia auricula, the second most cultivated mushroom in China, is not only nutritionally rich but also offers considerable health benefits. In particular, its polysaccharides have been widely recognized for their immunomodulatory activities, while its abundant protein content holds great promise as a raw material for developing immunomodulatory peptides. To meet the demand for high-value utilization of Auricularia auricula resources, this study developed a key technology for the stepwise extraction of polypeptides (AAPP1) and polysaccharides (AAPS3) using a composite enzymatic hydrolysis process. Their antioxidant and immunomodulatory effects were assessed using cyclophosphamide (CTX)-induced immune-suppressed mice. The results showed that both AAPP1 and AAPS3 significantly reversed CTX-induced decreases in thymus and spleen indices (p < 0.05); upregulated serum levels of cytokines (e.g., IL-4, TNF-α) and immunoglobulins (e.g., IgA, IgG); enhanced the activities of hepatic antioxidant enzymes SOD and CAT (p < 0.05); and reduced the content of MDA, a marker of oxidative damage. Intestinal microbiota analysis revealed that these compounds restored CTX-induced reductions in microbial α-diversity, increased the abundance of beneficial bacteria (Paramuribaculum, Prevotella; p < 0.05), decreased the proportion of pro-inflammatory Duncaniella, and reshaped the balance of the Bacteroidota/Firmicutes phyla. This study represents the first instance of synergistic extraction of polypeptides and polysaccharides from Auricularia auricula using a single process. It demonstrates their immune-enhancing effects through multiple mechanisms, including “antioxidation-immune organ repair-intestinal microbiota regulation.” The findings offer a theoretical and technical foundation for the deep processing of Auricularia auricula and the development of functional foods.