Possible beneficial effects of xyloglucan from its degradation by gut microbiota

Background: Xyloglucan (XyG) is a ubiquitous polysaccharide that possesses hypoglycemic effects, anti-hyperlipidemia effects, gut barrier protective properties, and positive effects on coronary heart disease. As a nonstarch polysaccharide, XyG cannot be processed directly by enzymes encoded on the human genome. After being ingested, XyG transits the large intestine where it becomes food for the intestinal microbial community. The species within the intestinal microbiota use various strategies to recognize and degrade XyG. However, most current studies focus on the industrial application of XyG. We must examine the beneficial effects of XyG on human health and the roles that the gut microbiota play in XyG degradation. Scope and approach: The current review summarizes the relationship between XyG and intestinal microbiota, including the degradation process of XyG by gut Bacteroidetes and the influence of XyG on the intestinal microbiota. In addition, the possible effects of XyG or its microbial degradation products on human health are presented. Key findings and conclusions: XyG breakdown in the large intestine is mediated by several proteins encoded on XyG utilization loci. Surface glycan-binding proteins and glycan-degrading enzymes encoded on XyG utilization loci are the main components that utilize XyGs in the large intestine. Secondary metabolites and fermentation end products that are generated in XyG degradation by gut microbiota can improve human health. The beneficial effects of XyG on human health may be realized through its microbial degradation.