Structure elucidation and intestinal barrier protection of an α-D-glucan in Huangshui

WLY-0, as an α-D-glucan with a molecular weight (Mw) of 11.12 kDa, was successfully isolated and purified from Huangshui (HS). The results of methylation and NMR indicated that the mainchain of WLY-0 was (1 → 4)-α-D-glucan, with side chains linking at O-6. Meanwhile, the surface morphology characterization showed that WLY-0 had an irregular flake-like morphology with a rough and uneven surface and varies in sizes from nanometers to microns. Furthermore, WLY-0 relieved the increased paracellular permeability of FD4 and decreased TEER challenged by LPS, meanwhile inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) and up-regulated the expression of TJ protein (Occludin, Claudin-1, ZO-1, and JAM-A) in Caco-2 cells, so to improve the intestinal barrier function. Our findings about the structural characteristics and biological activities of WLY-0 provided a scientific foundation for the utilization of HS as a potent source of an effective adjuvant in intestinal barrier injury treatment. [Display omitted] •A polysaccharide WLY-0 extracted from Huangshui, was identified as a α-D-glucan.•WLY-0 contains (1 → 4)-α-D-glucan in backbone, with side chains linking at O-6.•WLY-0 had an irregular flake-like morphology with a rough and uneven surface.•WLY-0 reversed LPS induced low TEER value and high FITC-dextran flux.•WLY-0 showed obvious intestinal barrier protective effect in vitro.