Digestion under saliva, simulated gastric and small intestinal conditions and fermentation in vitro by human gut microbiota of polysaccharides from Ficus carica Linn.

Previous studies have shown that Ficus carica polysaccharide (FCPS) extracted from common fig fruit exhibits antioxidant and immune-enhancing properties. Nevertheless, it remains uncertain whether FCPS can modulate the metabolism of gut microbiota. This study aims to assess whether the polysaccharides from two different types of figs can be broken down by the upper digestive system, including saliva, simulated stomach, and small intestinal conditions, and whether the gut microbiota can utilize them (Mw = 4.59 × 104 (LFCP, Low molecular weight), Mw = 6.08 × 104(HFCP, High molecular weight)). The results revealed that FCPS retained its molecular weight and reducing sugar content even after passing through the upper digestive system, indicating its safe arrival in the gut without undergoing decomposition. In vitro FCPS fermentation of gut microbiota lowered the pH and produced more gas in the order of LFCPHFCP, respectively, indicating that it can be broken down and utilized by the microbiota. Additionally, the amount of short-chain fatty acids increased notably (LFCP < HFCP), indicating the higher the molecular weight, the stronger the acid production capacity. FCPS demonstrated the ability to significantly decrease the Firmicutes to Bacteroidetes ratio, potentially inhibiting obesity and inflammation. Therefore, FCPS is a promising functional food with potential to enhance health and prevent disease by promoting gut health.