Structural characterization of Seabuckthorn polysaccharides and protective effects on acute alcoholic liver disease

In this paper, three homogeneous pectic polysaccharides, namely HRFP-II-a, HRFP-II-b, and HRFP-II-c, with molecular weights of 246.05, 85.64, and 15.56 kDa, were isolated from the Seabuckthorn fruits. A comparative structural characterization was conducted using extensive chemical, chromatographic, and spectroscopic methods. HRFP-II-a, HRFP-II-b, and HRFP-II-c were mainly composed of GalA, Gal, and Ara in different molar ratios, all of which exhibited characteristic pectic polysaccharide structures. Their protective effects were also evaluated in THLE-2 cells and in mice with alcohol-induced liver injury. The results showed that HRFP-II-a, HRFP-II-b, and HRFP-II-c attenuated ethanol-induced cellular damage by maintaining cellular structural integrity, inhibited the secretion of inflammatory factors to reduce the inflammatory response, and enhanced antioxidant capacity to mitigate oxidative stress. Meanwhile, the potential protective effects of HRFP-II on ALD mice were evaluated. HRFP-II treatment reduced serum levels of AST, ALT, TC, TG, and LDL-C, while elevating HDL-C levels. Additionally, it decreased hepatic MDA levels and increased CAT, SOD, and GSH levels, while reducing hepatic inflammatory factors. HRFP-II repaired the intestinal mucosal barrier by upregulating the expression of intestinal ZO-1 and Occludin, and altered the intestinal microbiota of ALD mice by decreasing the ratio of Bacteroides thickeningii to Bacteroides vulgatus, increasing the beneficial flora, and inhibiting the level of harmful bacteria. These findings suggested that HRFP-II may ameliorate ALD by modulating the gut-hepatic axis, and it could be an effective dietary supplement for the treatment of alcoholic liver disease.