Artificially fermented dark loose tea ameliorates metabolic-associated fatty liver disease by activating the PI3K/AKT signalling pathway and regulating gut microbiota dysbiosis.

Artificially fermented dark loose tea (AFT) has demonstrated potential lipid-lowering effects. However, the effects, including the dose-dependent effects, of AFT on metabolic-associated fatty liver disease (MAFLD) and their underlying mechanisms remain largely unclear. In vitro, AFT was found to effectively reduce intracellular lipid droplet formation and decrease the levels of total cholesterol and triglycerides. In vivo, AFT significantly prevented body weight gain, ameliorated serum lipid metabolism disorders, and alleviated hepatic steatosis. The ameliorative effect of AFT on MAFLD was associated with the activation of the PI3K/AKT signalling pathway, as indicated by the increased levels of phosphorylated (p)-PI3K/PI3K and p-AKT/AKT and the decreased expression of FOXO-1 and PEPCK at both the gene and protein levels. AFT supplementation regulated gut dysbiosis, especially in terms of reversing HFD-induced reductions in the relative abundances of Akkermansia and Lachnospiraceae NK4A136 group. In conclusion, AFT effectively ameliorated HFD-induced MAFLD in a dose-dependent manner.