BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a widespread metabolic liver disease. Colonic metabolic disorders and intestinal microecological imbalances have been confirmed as early driving factors and key therapeutic targets. Lycium barbarum l., a traditional Chinese medicinal plant, produces polyphenols (LBP), that have the potential to improve both NAFLD and colonic metabolism. However, the mechanism by which LBP alleviates NAFLD remains unclear.
PURPOSE: The aim of this study was to evaluate the mechanism and key targets of LBP in alleviating NAFLD, focusing on liver, colon metabolism, and intestinal flora.
METHODS: LBP was extracted and purified from Lycium barbarum l.. The NAFLD model was induced in C57BL/6 J mice by giving a high-fat diet and 5 % fructose water, and LBP was administered within 10 weeks. First, the composition of Lycium barbarum polyphenols was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Network pharmacology was used to identify potential therapeutic targets for LBP. The interventional effects of LBP on NAFLD mice were evaluated by liver and colon histopathology. Untargeted metabolomics analysis of the liver, colon, and colonic contents was performed by ultrahigh-performance liquid chromatography-mass spectrometry (UHPLCHRMS). Molecular docking and Western blot analysis of methionine adenosyltransferases (MAT1A and MAT2A) were combined to elucidate the underlying mechanisms. Short-chain fatty acids (SCFAs) content in colonic contents was further quantified. 16S rRNA sequencing was used to explore the role of LBP in ameliorating intestinal microbiota imbalance. Finally, Cytoscape was used to analyze the correlation between tissue metabolomes, liver phenotypes, and microbiota.
RESULTS: LBP can significantly alleviate the liver and colon pathological damage of NAFLD induced by a high-fat diet. Studies have identified rutin, astragaloside, isoquercitrin, luteolin and 4-coumaric acid as the main active components of LBP. LBP significantly reduced the levels of inflammatory markers in plasma, liver, and colon, including anti-tumor necrosis factor α (TNF-α), interleukin-10 (IL-10), and interleukin-6 (IL-6). Meanwhile, LBP restored the levels of superoxide dismutase (SOD), myeloperoxidase (MPO), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px) in liver and colon. Untargeted metabolomic analysis of the liver, colon, and colonic contents demonstrated the critical role of methionine cycle homeostasis, S-adenosylmethionine (SAM) biosynthesis, and reduced homocysteine ​​accumulation in the therapeutic effects of LBP. These findings were supported by molecular docking and Western blotting, which confirmed direct interactions of key polyphenols with methionine cycle enzymes (MAT1A and MAT2A). In addition, the dysregulated intestinal flora of NAFLD mice was improved by LBP, significantly affecting the following microorganisms: Paramuribaculum, Muribaculaceae, Eisenbergiell, Lactobacillus, and Akkermansia. Correlation analysis further demonstrated close associations between microbial shifts, methyl donor metabolism, and host phenotypes, highlighting the coordinated regulation of the gut-liver axis by LBP.
CONCLUSIONS: Multi-tissue metabolic analysis revealed that Lycium barbarum polyphenols can alleviate the development and progression of NAFLD by reshaping the colonic microbiota and regulating the methionine cycle and gut-liver axis metabolic balance. This highlights their potential as a functional food intervention for NAFLD.
