Dietary Bioactive Components
Objectives: Edible mushroom polysaccharides exhibited potential in modulating various biological processes. In the present study, the anti-inflammatory effects of two novel water-soluble polysaccharides from edible mushroom Pleurotus eryngii were investigated. Methods: Two novel polysaccharides PPEP-1 and PPEP-2 were isolated and purified from the mushroom by DEAE cellulose-52 chromatography and Sephadex G-200 size-exclusion chromatography. Molecular weights and monosaccharide analysis were determined by high-performance size-exclusion chromatography (HPSEC) and gas chromatography (GC), respectively. Infrared spectrum (FT-IR) was applied to analyze the functional groups of the two polysaccharides. At last, the anti-inflammatory effects of PPEP-1 and PPEP-2 were revealed in LPS-stimulated RAW264.7 macrophages. Results: The molecular weights of PPEP-1 and PPEP-2 were found to be 167 kDa and 274 kDa, respectively. GC analysis indicated that PPEP-1 and PPEP-2 were heterpolysaccharides and mainly composed of glucose. FT-IR revealed both PPEP-1 and PPEP-2 were mainly consisted of β-type glycosidic linkages. Direct exposure to PPEP-1 and PPEP-2 significantly inhibited the LPS-induced inflammatory responses of RAW 264.7 macrophages by inhibiting the production of nitric oxide (NO), prostaglandin E2 (PGE2), IL-1β, TNF-α and IL-6. PPEP-1 and PPEP-2 inhibited the activation of MAPK pathways by inhibiting phosphorylation of p38, extracellular regulated protein kinases 1/2 (ERK1/2) and stress-activated protein kinase/jun aminoterminal kinase (SAPK/JNK). Moreover, PPEP-1 and PPEP-2 also inhibited NF-κB signaling by reducing the nuclear translocation and phosphorylation of p65. Conclusions: Overall, our results for the first time, demonstrated the anti-inflammatory effects of two novel polysaccharides from the edible mushroom Pleurotus eryngii and highlighted the potential benefits of using the polysaccharides as anti-inflammatory agents in functional foods and/or dietary supplements to combat inflammatory diseases.