In vitro digestive and fermentation characterization of Polygonatum cyrtonema polysaccharide and its effects on human gut microbiota

Polygonatum cyrtonema polysaccharide (PCP) was subjected to simulated gastrointestinal digestion, followed by in vitro fermentation using human gut microbiota organisms. The results indicated that PCP did not degrade under simulated salivary conditions; however, a certain increase in reducing sugars and monosaccharides, and a slight reduction in the molecular weight of PCP in the gastrointestinal tract were observed, suggesting the partial degradation of PCP. During in vitro fermentation, a large proportion of PCP was degraded by the gut microbiota in fecal samples from both healthy and obese people. The utilization of PCP by the gut microbiota resulted in the generation of abundant short-chain fatty acids (SCFAs), leading to a reduction in environmental pH and stimulation of the proliferation of beneficial bacteria, such as Collinsella and Dialister, while impeding the growth of detrimental bacteria like Flavonifractor. The gut microbiota of healthy individuals exhibited greater efficiency in utilizing PCP compared to that of obese individuals. PICRUSt prediction analysis indicated that the regulation of the gut microbiota by PCP was mainly linked to carbohydrate, amino acid, energy, and lipid metabolic pathways. These results suggested that PCP may promote host health by modulating the gut microbiota and exhibiting potential prebiotic properties.