Polysaccharides from Hericium erinaceus Fruiting Bodies: Structural Characterization, Immunomodulatory Activity and Mechanism

Five fractions from crude Hericium erinaceus polysaccharides (HEPs), including HEP-1, HEP-2, HEP-3, HEP-4 and HEP-5, were obtained through column chromatography with a DEAE Cellulose-52 column and Sephadex G-100 column. The contents of total carbohydrates and uronic acid in HEPs were 53.36% and 32.56%, respectively. HEPs were mainly composed of Fuc, Gal and Glu in a molar ratio of 7.9:68.4:23.7. Its chemical structure was characterized by sugar and methylation analysis, along with 1H and 13C NMR spectroscopy. HEP-1 contains the backbone composed of (1→6)-linked-galactose with branches attached to O-2 of some glucose. The immunological activity assay indicated that HEP-1 significantly promoted the production of nitric oxide, interleukin-6, interleukin-10, interferon-γ and tumor necrosis factor-α and the phosphorylation of signaling molecules. Collectively, these results suggested that HEP-1 could improve immunity via NF-κB, MAPK and PI3K/Akt pathways. Hericium erinaceus polysaccharides might be explored as an immunomodulatory agent for use in dietary supplements.