The Conversion of Black Chokeberry Condensed Tannins into Anthocyanidins Has a Better Reparative Effect on the Imbalance of Gut Microbiota and Metabolites Caused by a High-Salt Diet

Black chokeberry is rich in polyphenols, but its high-content polymeric condensed tannins impair gut microbiota, while anthocyanins exert beneficial regulatory effects. This study compared the reparative effects and metabolic changes of black chokeberry extracts (BCE: rich in condensed tannins) and conversion treatment black chokeberry extracts (CTBCE: converts condensed tannins into cyanidin) on gut microbiota imbalance caused by a high-salt diet. Results showed that a high-salt diet significantly reduced Lactobacillus abundance, and intervention with two extracts can effectively restore the relative abundance of Lactobacillus. However, BCE decreased gut microbial diversity in a dose-dependent manner, whereas CTBCE elevated microbial diversity and restored Lactobacillus, Bifidobacterium, and Oscillospira. CTBCE also recovered fecal metabolites, including 6-ketoprostaglandin E1 and indole-2-one. Reducing the proportion of condensed tannins and increasing the proportion of anthocyanins effectively improved the regulatory capacity of gut microbiota, it is possible to improve its repair effect on gut microbiota and metabolic abnormalities caused by a high-salt diet.