Role of the Gut Microbiota and Their Metabolites in Modulating the Cholesterol-Lowering Effects of Citrus Pectin Oligosaccharides in C57BL/6 Mice

We investigated the regulatory effects of citrus pectin oligosaccharides (POS) from an innovative, chemically controllable degradation process on cholesterol metabolism and the gut microbial composition. The modulatory role of the intestinal flora was explored. Four-week-old male CS7BL/6 mice were fed either a standard diet; a high-fat (HF) diet; or a HF diet with 0.15, 0.45, and 0.9 g/kg body weight POS for 30 days. POS reduced serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) in a dose-dependent manner. The relative abundances of specific bacterial groups in the feces and the concentrations of their metabolites were higher in the POS groups. There were significant correlations among Bifidobacterium, Lactobacillus, and Bacteroides and short-chain fatty acids, as well as among serum TC, LDL-C, fecal bile acids, and liver cholesterol 7-alpha-hydroxylase and 3-hydroxy-3-methylglutaryl-coenzyme A reductase. These findings indicate that the prepared POS exhibited hypocholesterolemic effects and that the potential regulatory mechanisms of citrus POS on cholesterol metabolism are modulated by specific bacterial groups together with their metabolites.