Structural Characterization and Immunomodulatory Effects of Polysaccharide PCP-1 from Pleurotus citrinopileatus

The use of fungal polysaccharides as immunomodulators has garnered significant interest. Here, the polysaccharide PCP-1 is isolated and purified from the fruiting bodies of Pleurotus citrinopileatus. PCP-1 is identified as a glucan with a molecular weight of 1670 kDa. Methylation analysis reveals that PCP-1 consists of T-Glcp, T-Rhap, 1,3-Glcp, 1,4-Glcp, 1,4,6-Glcp, and 1,3,6-Glcp. PCP-1 exhibits exceptional immunomodulatory effects, as it can dose-dependently stimulate phagocytosis and promote the secretion of nitric oxide and reactive oxygen species in RAW264.7 cells. Additionally, PCP-1 significantly enhances the secretion of cytokines such as TNF-alpha, IL-1 beta, and IL-6 at both the protein and mRNA levels, with concentrations ranging from 2.5 to 40 mu g mL(-1). At a concentration of 40 mu g mL(-1), the immunomodulatory effects are comparable to those of the positive control. Furthermore, PCP-1 promotes the nuclear translocation of the p65 protein, indicating activation of the NF-kappa B signaling pathway. The results demonstrate that PCP-1 has the potential as a natural immunomodulator, with possible applications in the food, pharmaceutical, and other industries.