In vitro digestion and fecal fermentation profiles of Cremastra appendiculata polysaccharide and evaluation of its antioxidant and hypoglycemic capacities

Abstract Aims Cremastra appendiculata is a traditional Chinese herbal medicine for liver cancer treatment. C. appendiculata polysaccharides (CAP) as a biomacromolecular showed significant lipid-lowering activities. However, the gastrointestinal metabolic fate and the bioactivities of the fermented products remain poorly understood. Methods and Results Simulated salivary, gastric, intestinal digestion models, together with an in vitro human fecal fermentation system, were employed to evaluate the physicochemical profiles of CAP. Variations in molecular weight, reducing sugars, free monosaccharides, short-chain fatty acids (SCFAs), and pH were determined. 16S rRNA gene sequencing was performed to characterize alterations in fecal fermentation microbial communities, and the in vitro α-amylase and α-glucosidase inhibitory activities and antioxidant activities were assessed. As a result, during the simulated fermentation process, CAP remained structurally stable throughout simulated gastrointestinal digestion. During fecal fermentation, CAP was degraded by the fecal microbiota as the molecular weight decreased and the reducing sugars increased. Moreover, CAP significantly enhanced SCFAs production, particularly acetic acid and propionic acid, with a reduction in fermentation pH. CAP selectively enriched beneficial bacteria, including Bifidobacterium, Bacteroides, Lactobacillus and Odoribacter, while suppressing potentially harmful microorganisms, such as Proteobacteria, Bilophila, and Eggerthella. Furthermore, fecal fermentation of CAP enhanced inhibitory effects against α-amylase and α-glucosidase and antioxidant activities. Conclusions These findings provide mechanistic insights into the health-promoting properties of CAP and support its future development as a functional food ingredient and gut microbiota regulator.