[Regulation of Bifidobacterium-short chain fatty acid metabolism and improvement of intestinal toxicity of vinegar-processed Euphorbiae Pekinensis Radix].

Abstract

To explore the mechanism by which vinegar-processed Euphorbiae Pekinensis Radix regulates gut microbiota and reduces intestinal toxicity, this study aimed to identify key microbial communities related to vinegar-induced detoxification and verify their functions. Using a derivatization method, the study measured the content of short-chain fatty acids(SCFAs) in feces before and after vinegar-processing of Euphorbiae Pekinensis Radix. Combined with the results of previous gut microbiota sequencing, correlation analysis was used to identify key microbial communities related to SCFAs content. Through single-bacterium transplantation experiments, the role of key microbial communities in regulating SCFAs metabolism and alleviating the intestinal toxicity of Euphorbiae Pekinensis Radix was clarified. Fecal extracts were then added to a co-culture system of Caco-2 and RAW264.7 cells, and toxicity differences were evaluated using intestinal tight junction proteins and inflammatory factors as indicators. Additionally, the application of a SCFAs receptor blocker helped confirm the role of SCFAs in reducing intestinal toxicity during vinegar-processing of Euphorbiae Pekinensis Radix. The results of this study indicated that vinegar-processing of Euphorbiae Pekinensis Radix improved the decline in SCFAs content caused by the raw material. Correlation analysis revealed that Bifidobacterium was positively correlated with the levels of acetic acid, propionic acid, isobutyric acid, n-butyric acid, isovaleric acid, and n-valeric acid. RESULTS:: from single-bacterium transplantation experiments demonstrated that Bifidobacterium could mitigate the reduction in SCFAs content induced by raw Euphorbiae Pekinensis Radix, enhance the expression of tight junction proteins, and reduce intestinal inflammation. Similarly, cell experiment results confirmed that fecal extracts from Bifidobacterium-transplanted mice alleviated inflammation and increased the expression of tight junction proteins in intestinal epithelial cells. The use of the free fatty acid receptor-2 inhibitor GLPG0974 verified that this improvement effect was related to the SCFAs pathway. This study demonstrates that Bifidobacterium is the key microbial community responsible for reducing intestinal toxicity in vinegar-processed Euphorbiae Pekinensis Radix. Vinegar-processing increases the abundance of Bifidobacterium, elevates the intestinal SCFAs content, inhibits intestinal inflammation, and enhances the expression of tight junction proteins, thereby improving the intestinal toxicity of Euphorbiae Pekinensis Radix.