Isolation, purification, structure characterization of a novel glucan from Huangshui, a byproduct of Chinese Baijiu, and its immunomodulatory activity in LPS-stimulated THP-1 cells

Abstract

Huangshui (HS) has attracted considerable attention for the utilization of aroma compounds and microorganisms containing presently. However, little work has been done on biological polysaccharides in HS. In this study, a novel water-eluted HS polysaccharide, HSP-W, was identified as an α-D-glucan with a Mw of 166.00 kDa. It was consisted of a 1,4 linked α-D-Glcp backbone with the substitution at O-6 with 1,6-linked α-D-Glcp residue and non-reducing terminal of β-Glc-1→ through monosaccharide composition, IR, methylation, and NMR analyses. SEM, AFM, and particle size distribution measurements showed that HSP-W had relatively clustered spherical shape with different sizes from nanoscale to micrometer. Additionally, HSP-W significantly induced NO and ROS production as well as the release of IL-1β, IFN-γ, TNF-α, and IL-6, and upregulated pinocytic and phagocytic capacities of THP-1 cells. Meanwhile, HSP-W treatment markedly enhanced mRNA and protein expressions of these cytokines. HS probably has potential application as an immunostimulatory agent.