Astragalus membranaceus (Astragalus) is often used as a medical and food resource in China. The present study was designed to investigate the features and effects of polysaccharide from Astragalus membranaceus (WAP) on rats with antibiotic-associated diarrhea (AAD). WAP was mainly composed of glucose, galactose, arabinose and glacturonic acid, with glucan, arabinogalactan and RG-I regions, and it showed loosely irregular sheet conformation. WAP decreased the inflammatory cell infiltration of colon in AAD rats, increased propionate and butyrate production, improved metabolic levels, adjusted the diversity and composition of gut microbiota, increased the relative abundance of Pseudomonas, and decreased the relative abundance of Allobaculum and Coprococcus. In conclusion, WAP contained different types of polysaccharide regions and sheet three-dimensional conformation, while it ameliorated AAD by recovering the colon structure, adjusting the gut microbiota, and improving the SCFAs levels. The results can provide some data basis for natural products to alleviate the side effects related to antibiotics.

Polysaccharides from Panax ginseng are natural carbohydrates with multiple activities. However, little was known about its functions on colitis. In this study, we aim to investigate the protective effects of ginseng polysaccharides and its effective subfraction on dextran sodium sulfate (DSS)-induced colitis. Water soluble ginseng polysaccharides (WGP) were obtained from dry ginseng root, then purified to neutral fraction (WGPN) and acidic fraction (WGPA) by ion exchange chromatography. An animal model was constructed with male Wistar rats, which were treated with a normal diet (con group), DSS (DSS group), WGP (WGP group), WGPN (WGPN group), and WGPA (WGPA group), respectively. Both WGP and WGPA alleviated the colitis symptoms and colon structure changes of colitis rats. They decreased the disease activity index (DAI) scores and improved colon health; reduced colon damage and recovered the intestinal barrier via regulating the tight-junction-related proteins (ZO-1 and Occludin); downregulated inflammatory cytokines (IL-1β, IL-2, IL-6, and IL-17) and inhibited the TLR4/MyD88/NF-κB-signaling pathway in the colon; regulated the diversity and composition of gut microbiota, especially the relative abundance of Ruminococcus; enhanced the production of SCFAs. In conclusion, WGP exerted a protective effect against colitis with its acidic fraction (WGPA) as an effective fraction. The results support the utilization and investigation of ginseng polysaccharides as a potential intervention strategy for the prevention of colitis.

American ginseng (Panax quinquefolius L.) is an herbal medicine with polysaccharides as its important active ingredient. The purpose of this research was to identify the effects of the polysaccharides of P. quinquefolius (WQP) on rats with antibiotic-associated diarrhoea (AAD) induced by lincomycin hydrochloride. WQP was primarily composed of galacturonic acid, glucose, galactose, and arabinose. The yield, total sugar content, uronic acid content, and protein content were 6.71%, 85.2%, 31.9%, and 2.1%, respectively. WQP reduced the infiltration of inflammatory cells into the ileum and colon, reduced the IL-1β, IL-6, IL-17A, and TNF-α levels, increased the levels of IL-4 and IL-10 in colon tissues, improved the production of acetate and propionate, regulated the gut microbiota diversity and composition, improved the relative richness of Lactobacillus and Bacteroides, and reduced the relative richness of Blautia and Coprococcus. The results indicated that WQP can enhance the recovery of the intestinal structure in rats, reduce inflammatory cytokine levels, improve short-chain fatty acid (SCFA) levels, promote recovery of the gut microbiota and intestinal mucosal barrier, and alleviate antibiotic-related side effects such as diarrhoea and microbiota dysbiosis caused by lincomycin hydrochloride. We found that WQP can protect the intestinal barrier by increasing Occludin and Claudin-1 expression. In addition, WQP inhibited the MAPK inflammatory signaling pathway to improve the inflammatory status. This study provides a foundation for the treatment of natural polysaccharides to reduce antibiotic-related side effects.