Abstract: The effects of anthocyanins in red wine on the human intestinal microbiota in vitro were investigated in this study. By 16S rRNA gene sequencing, the changes in the abundance, diversity and functional genes of the intestinal microbiota were investigated after being cultured in vitro for up to 24 h in the presence of freeze-dried red wine or malvidin-3-O-glucoside as the major anthocyanin in red wine. The structure and function of the intestinal microbiota were also analyzed. The results showed that high concentration of anthocyanins and malvidin-3-O-glucoside in wine could reduce the Firmicutes/Bacteroidetes (F/B) ratio by 32.98% and 60.43% between zero and 24 h of culture, respectively. Anthocyanins in wine could also effectively delay the reduction in the relative abundance of Actinobacteria and Lactobacillus and reduce the relative abundance of the harmful bacteria Escherichia-Shigella and Klebsiella by 66.36% and 33.33% between zero and 24 h, respectively. Furthermore, both anthocyanins and malvidin-3-O-glucoside in wine enhanced the expression of metabolism-related genes in the intestinal microbiota, especially for lipid metabolism and energy metabolism. Conclusion: Anthocyanins in red wine can regulate the structure and composition of the intestinal microbiota through promoting the growth of probiotics and inhibiting the growth of pathogenic bacteria, and consequently improve human intestinal metabolism.

Key words: red wine; anthocyanins; intestinal microbiota; fermentation in vitro; 16S rRNA gene sequencing