Immunomodulation effect of polysaccharides from liquid fermentation of Monascus purpureus 40269 via membrane TLR-4 to activate the MAPK and NF-κB signaling pathways

A polysaccharide (EMP) was prepared from Monascus purpureus 40,269 through liquid fermentation, and its immunoregulatory effect was investigated to find clues regarding its potential applicability. Structural characterization demonstrated that EMP, with a molecular weight of 83.1 kDa, consists of Xyl, Man, Gal, Ara, Rha, Glc, GalA, and GlcA at a molar ratio of 2.6: 22: 35.1: 7: 1: 29.2: 2.7: 0.6. Immunomodulatory assays involving RAW264.7 cells indicated that EMP exhibits significantly enhanced pinocytic and phagocytic capacities and promotes the secretion of reactive oxygen species, nitric oxide, and cytokines (interleukin-1β, tumor necrosis factor-α, and interleukin-6) by activating RAW264.7 cells. Moreover, EMP is recognized by Toll-like receptor 4 (TLR-4) and has an immunomodulatory effect by activating the mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways in RAW264.7 cells. Collectively, these results demonstrate that EMP could be used as a functional food for immunological reagents.