Structural characterization and immuno-stimulating activities of a novel polysaccharide from Huangshui, a byproduct of Chinese Baijiu.

Huangshui (HS), a byproduct of Baijiu, has been widely studied for the utilization of aromatic compounds and microorganisms. However, there is little information on the bioactive polysaccharides in HS. In this study, a novel complex polysaccharide (HSP-2) composed of mannose, glucose, galactose, arabinose, xylose, and rhamnose at approximate percentages of 53.0, 29.6, 11.5, 2.7, 2.1, and 1.0, respectively, was successfully extracted and purified from HS. The results of FT-IR, methylation analysis, and NMR showed that the backbone of HSP-2 was → 2)-β-D-Manp-(1 → 2,6)-β-D-Manp-(1 → 6)-α-D-Glcp-(1 → 4)-α-L-Rhap-(1 → 3,4)-α-L-Rhap-(1→. In addition, HSP-2 showed significant immuno-stimulating effects via increasing the ROS and NO generation, and enhancing the pinocytic and phagocytic capacities of THP-1 cells in a dose-dependent manner. Meanwhile, HSP-2 treatment increased IFN-γ, TNF-α, IL-6 and IL-1β secretion through activating the expression of the related mRNAs and proteins. These results will provide a molecular basis for immuno-stimulating effects of HSP-2 and lay a foundation for the potential application of HS in functional foods.