Fu Brick
tea belongs to fermented dark
tea, which is one of the six categories of
tea. Fu Brick
tea has been reported to reduce adiposity and has beneficial effects in the treatment of
hypercholesterolemia and
cardiovascular disease.
Theabrownin (TB) is one of the pigments with the most abundant content in Fu Brick
tea. TB has also been reported to have
lipid-lowering effects, but its mechanism remains unclear. We found that TB could effectively reduce the
insulin resistance and fat deposition induced by a high fat diet (HFD), decrease
inflammation in the liver, improve intestinal integrity, and reduce
endotoxins in circulation. Further studies showed that TB increased the abundance of Verrucomicrobiota and reduced the abundance of Firmicutes and Desulfobacterota in the intestinal tract of obese mice. The alteration of gut microbiota is closely linked to the metabolic phenotype after TB treatment through correlation analysis. Moreover, TB changed the gut microbial metabolites including L-
ornithine, α-ketoglutarate, and
glutamine, which have also been found to be upregulated in the liver after TB intervention. In vitro, L-
ornithine, α-ketoglutarate, or
glutamine significantly reduced
lipopolysaccharide (LPS)-induced
inflammation in macrophages. Therefore, our results suggest that TB can reduce adiposity, systemic
insulin resistance, and liver
inflammation induced by a HFD through altering gut microbiota and improving the intestinal tight junction integrity. The metabolites of gut microbiota might also play a role in ameliorating the HFD-induced phenotype by TB.