Catabolism of phenolics from grape peel and its effects on gut microbiota during in vitro colonic fermentation

Grape peels, the main by-products of wine processing, are rich in bioactive ingredients of phenolics, including proanthocyanidins, flavonoids and anthocyanins. Phenolics have the function of regulating intestinal microbiota and promoting intestinal health. From the perspective of the dietary nutrition of grape peel phenolics (GPP), the present study aimed to investigate the influence of GPP on the composition and metabolism of human gut microbiota during in vitro fermentation.

The results indicated that GPP could decrease pH and promote the production of short-chain fatty acids. ACE and Chao1 indices in GPP group were lower than that of the Blank group. GPP enhanced the levels of Lachnospiraceae UCG-004, Bacteroidetes and Roseburia, but reduced the Firmicutes/Bacteroidetes ratio. Kyoto Encyclopedia of Proteins and Genome enrichment pathways related to phenolic acid metabolism mainly included flavonoid, anthocyanin, flavone and flavonol biosynthesis. Gut microbiota could accelerate the release and breakdown of phenolic compounds, resulting in a decrease in the content of hesperetin-7-O-glucoside, delphinidin-3-O-glucoside and cyanidin-3-rutinoside etc. In vitro antibacterial test found that GPP increased the diameters of the inhibition zones of Escherichia coli and Staphylococcus aureus in a dose-dependent manner.

The results of the present study revealed that GPP might be a potential prebiotic-like to prevent diseases by improving gut health. The findings could provide a theoretical basis for the potential to exploit GPP as dietary nutrition to maintain intestinal function. © 2024 Society of Chemical Industry.