Proteins from edible mushrooms have a variety of biological activities. Here, thirteen precious edible mushrooms such asOphiocordyceps sinensis,Ganoderma lucidum, andMorchella esculentaand nine common edible mushrooms such asFlammulina velutipes,Pleurotus ostreatus, andPleurotus eryngii, etc., from which their proteins were extracted, their composition analyzed and their immunomodulatory activity assessed. Rare mushrooms are a species of edible mushrooms with higher edible value and medicinal value than common edible mushrooms. The results showed that all the different edible mushroom crude proteins increased the proliferation and phagocytosis of mouse macrophages, and we found that these edible mushroom proteins affected the secretion of reactive oxygen species and nitric oxide by mouse macrophages. Further studies on cytokines secreted by mouse macrophages showed a significant increase in pro-inflammatory cytokines, suggesting that edible mushroom proteins promote the polarisation of macrophages into classical M1-type macrophages, further demonstrating that edible mushroom proteins enhance immunity. It was also found that the immunomodulatory activity of the precious edible mushroom proteins was significantly higher than that of the common edible mushroom proteins. These results have important implications for the processing and product development of edible mushroom proteins.

Natural polysaccharides named PEP-0.1-1, PEP-0-1 and PEP-0-2 from edible mushroom species Pleurotus eryngii were obtained in the present study. Results showed that molecular weights of these polysaccharides were 3235 kDa, 2041 kDa and 23933 Da, respectively. Further, structural characterization revealed that PEP-0.1-1 had a →4-α-D-Glcp-1→ backbone and contained →4)-α-D-Glcp and →4)-β-D-Glcp reducing end groups. PEP-0-1 backbone contained →4-α-D-Glcp-1→ and →6-α-3-O-Me-D-Galp-1→, and the side chains contained α-D-Glcp, β-D-Manp-1→ and α-D-Glcp-3→. However, PEP-0-2 backbone consisted of →4-α-D-Glcp-1→ and →6-α-3-O-Me-D-Galp-(1→6)-α-D-Galp-1→ while the side chains contained α-D-Glcp and β-D-Manp-1→. Biological activity analysis was then carried out and found that all these polysaccharides could significantly suppress the relative mRNA expression of TLR4, nitric oxide (NO), TNF-α, IL-1β and IL-6 in lipopolysaccharide (LPS)-induced inflammation of RAW 264.7 cells, as well as the over secretion of the above cell cytokines. Moreover, western blotting analysis revealed that all these purified fractions displayed significant inhibition effects on the expression of JNK protein induced by LPS in MAPK pathway, along with the relieving on the inhibition effect of LPS on IκB-α protein expression. In summary, the information generated by the present study could provide a theoretical basis for the exploration of novel healthy food materials from edible mushroom with anti-inflammation activities.