Barley Vinegar Relieves Loperamide-Induced Constipation in Mice via the Modulation of the Gut Microbiota and Serum Metabolism

This study investigated the effect of barley vinegar on constipation by regulating the structure of intestinal microbiota and the level of short-chain fatty acids (SCFAs). BALB/c mice with loperamide-induced constipation were treated with barley vinegar in the intervention. After treatment, constipation-related factors were identified. The effect of barley vinegar on the composition of the intestinal microbiota was evaluated by means of 16S rDNA gene sequencing, and the content of SCFAs in enteral feces was determined via the GC-MS method. Treating constipated mice with barley vinegar accelerated gastrointestinal peristalsis, inhibited the inflammatory response, protected the intestinal barrier, upregulated the production of beneficial intestinal bacteria, and downregulated the production of harmful intestinal bacteria. These therapeutic effects are attributed to reversed gut microbiota dysfunction, which favors the production of intestinal metabolites such as SCFAs. The purgative function of highland barley vinegar may improve the intestinal environment by regulating the balance of intestinal flora and the concentration of SCFAs. In addition, LC-MS metabolomics was used to analyze the effect of barley vinegar on intestinal metabolites in mice with constipation. The results show that the treatment of barley vinegar inhibited the decrease in aspartate, L-threonine, L-serine, L-proline, 3,4-dihydroxymandelic acid, epinephrine, glyceric acid, and 3,4-dihydroxymandelic acid content in intestinal metabolites caused by constipation. 4-2 hydroxy benzene acetic acid and fumaric acid content increased. KEGG pathway analysis showed that digestive system, amino acid and lipid metabolism pathways were important pathways for highland barley vinegar relieving constipation. This study proves that highland barley vinegar mainly regulates lipid metabolism, the digestive system and amino acid metabolism to maintain a steady state, prevent intestinal injury, and improve constipation. In short, this study demonstrates that highland barley vinegar can alleviate constipation in mice and repair colitis damage.