Four polysaccharides isolated from Poria cocos mycelium and fermentation broth supernatant possess different activities on regulating immune response

Four polysaccharide fractions were isolated and purified from the culture supernatant and mycelium of Poria cocos, and differences in their immunomodulatory activity were investigated. The average molecular weights of EPS-0M, EPS-0.1M, IPS-0M, and IPS-0.1M were 1.77 x 103, 2.01 x 103, 0.03 x 103 and 4.97 x 103 kDa, respectively. They all mainly consisted of 5 monosaccharides, including glucose, mannose, galactose, fucose and rhamnose, but with different molar ratios. At a dose of 50 mu g/mL, EPS-0M, EPS-0.1M, and IPS-0.1M significantly increased the production of nitric oxide (NO), as well as the mRNA and protein levels of pro-inflammatory factors including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta) in RAW264.7 cells, suggesting that they enhanced macrophage-mediated innate immunity. Moreover, based on the in vitro inflammation model of lipopolysaccharide (LPS)-stimulated RAW264.7 cells, EPS-0M, EPS-0.1M and IPS-0M but not IPS-0.1M could inhibit the LPS-induced excessive inflammatory response, including NO, IL-6, TNF-alpha, IL-1 beta production and gene transcription. Interestingly, IPS-0M showed a relatively poor immunostimulatory effect, but had the strongest inhibitory effect against the LPS-induced RAW264.7 inflammatory response. Furthermore, our results indicate that the nuclear factor-kappa B (NF-kappa B) pathway is associated with the immunomodulatory ef-fects of the polysaccharide samples on RAW264.7 cells. This study can provide a reference for the more targeted application of different polysaccharide components from Poria cocos for human health.

Automated summary

Four polysaccharide fractions were isolated from Poria cocos and investigated for their immunomodulatory activity. They mainly consisted of glucose, mannose, galactose, fucose, and rhamnose, but with different ratios. These polysaccharides enhanced macrophage-mediated innate immunity and inhibited excessive inflammatory response.