BACKGROUND: Arctigenin (AG), a phenylpropanoid lignan from the medicinal and food homologous plant Arctium lappa l., is known for its anti-cancer, anti-inflammatory and antioxidant properties. However, the pharmacological effects of AG on metabolic disorders remain limited, and specific mechanisms based on gut microbiota have not been reported.
PURPOSE: This study aimed to evaluate the regulation of glycolipid metabolism by AG in obese mice and investigate the potential mechanisms associated with gut microbes.
METHODS: The anti-obesity efficacy of AG was evaluated in high-fat diet (HFD)-fed mice. 16S rRNA gene sequencing and GC-MS were used to detect changes in gut microbes and metabolite levels. Immunohistochemistry, immunofluorescence, and polymerase chain reaction were used to validate the molecular mechanisms of gut microbe-derived metabolites involved in the improvement of intestinal homeostasis and hepatic metabolism by AG.
RESULTS: We found that AG significantly ameliorated HFD-induced glucolipid metabolism disorders, liver degeneration and the imbalance of macrophage M1/M2 polarization. In addition, AG attenuated intestinal barrier damage, inflammation and imbalance of Th17/Treg immune in HFD mice. Importantly, AG promoted short-chain fatty acid (SCFA)-producing bacteria and SCFA levels, which regulated the G protein-coupled receptor (GPR)41/43 and HDAC3 pathways to induce FOXP3 protein expression and consequently maintained intestinal Th17/Treg immunity. AG also inhibited lipopolysaccharide (LPS) production leading to attenuation of TLR4/NF-κB-mediated intestinal inflammation. Furthermore, AG upregulated intestinal MCT1 protein levels to promote absorption of SCFA and activated the hepatic GPR41/43/109a-AMPK pathway to regulate lipid metabolism, and thus reduced lipid accumulation.
CONCLUSION: This study first demonstrated that AG could modulate the gut microbiota and derived metabolites to repair intestinal damage and regulate hepatic metabolic pathways, thereby ameliorating metabolic disorders induced by HFD. These findings support the great potential of AG as a novel prebiotic to fight obesity and chronic metabolic diseases by targeting the gut microbiota.
