Digestive properties in fermentation driven interactions of plant polysaccharides with gut microbiota and their health implications

Plant polysaccharides, as pivotal dietary metabolites, primarily exert their health-promoting effects through interactions with the gut microbiota. These carbohydrates are resistant to digestion in the upper gastrointestinal tract and can reach the colon intact, where they are fermented by the gut microbiota to produce a variety of bioactive metabolites. Notably, the bioactivities of plant polysaccharides rely on microbial fermentation rather than direct absorption by the host. Gut microorganisms degrade diverse plant polysaccharides using carbohydrate-active enzymes (CAZymes) encoded by polysaccharide utilization loci (PULs) and via cross-feeding mechanisms.This paper systematically reviews the fermentation-driven dynamic interactions between plant polysaccharides and the gut microbiota, focusing on five core aspects: (1) The digestive resistance of plant polysaccharides as a prerequisite for colonic fermentation; (2) Microbial degradation mechanisms of plant polysaccharides; (3) Changes in the physicochemical properties and structure of plant polysaccharides during fermentation and their effects on bioactivity; (4) Selective proliferation of beneficial bacteria and regulation of microbial metabolism by specific polysaccharides acting as prebiotics; (5) Health benefits of plant polysaccharides mediated by the gut microbiota. By integrating recent advances in the digestibility of plant polysaccharides and microbial fermentation mechanisms, this paper comprehensively elucidates the complex regulatory network underlying the bioactivities of plant polysaccharides, and provides a scientific basis for the targeted application of these natural products in promoting human health and preventing diseases.