Modulation of Intestinal Flora by Plant Polyphenols Based on in Vitro Fermentation Models

To explore the potential prebiotic effects of plant-derived polyphenols, this study compared the inhibitory effects of tea polyphenols, apple polyphenols, grape seed polyphenols, and peanut skin polyphenols on foodborne pathogenic bacteria. Furthermore, in vitro simulated fermentation was conducted to evaluate their modulation effects on gut microbiota. The results revealed that tea polyphenols and apple polyphenols exhibited stronger inhibitory activity against pathogenic bacteria, with 1.25 mg/mL of tea polyphenols or 2.5 mg/mL of apple polyphenols significantly suppressing the growth of tested foodborne pathogens. Additionally, both tea and apple polyphenols showed relatively high antioxidant activity during in vitro simulated fermentation, with their DPPH radical scavenging capacities increasing by 7.00% and 7.69%, respectively. Regarding short-chain fatty acids (SCFAs) production, apple polyphenols, grape seed polyphenols, and peanut skin polyphenols notably elevated propionic and n-butyric acid concentrations (118% to 125% and 115% to 123% of the negative control, respectively) (P<0.05). Gut microbiota analysis revealed that tea polyphenols, apple polyphenols, and grape seed polyphenols reduced the abundance of Escherichia-Shigella while promoting the growth of beneficial bacterial taxa. Specifically, tea and apple polyphenols increased the abundance of Peptostreptococcus, whereas grape seed polyphenols uniquely modulated Clostridium levels. In conclusion, plant-derived polyphenols from different sources displayed distinct advantages in anti-bacterial activity, antioxidant capacity, and microbiota modulation. Notably, tea polyphenols showed particularly remarkable prebiotic properties. This study provides critical theoretical insights for the screening of plant polyphenol-based prebiotics and the development of synergistic formulations.