Saccharide-bearing macromolecules with melanoidin characteristics from Shanxi aged vinegar exert immunoenhancing effects on macrophage RAW264.7 cells

Bioactive macromolecule mining is important for the functional chemome dissection of traditional Chinese vinegar. Here, saccharide-bearing macromolecules in Shanxi aged vinegar (SBMSAV) were isolated, characterized, and their immunomodulatory activity was evaluated. Four sub-fractions were obtained through ethanol precipitation followed by refining and DEAE-650M column chromatography. All sub-fractions had a maximum molecular weight of more than 2,667 kDa, with 10 types of monosaccharides identified. Comparative analysis of these sub-fractions with melanoidins from real food and model systems showed that all four sub-fractions had similarities with both melanoidins in elemental composition, spectral signature, and pyrolytic characteristics. Immunological assays showed that the four sub-fractions significantly improved macrophage cell viability and phagocytic activity, and promoted the secretion of NO, TNF-α, and IL-6. Immunomodulatory mechanism investigation indicated that SBMSAV enhanced aerobic glycolysis in macrophages and were recognized through TLR2, TLR4, MR, SR, and Dectin-1. Additionally, the MyD88/PI3K/Akt/NF-κB signaling pathway was found to be involved in the activation of macrophages.