Eubacterium sp. mediates the anti-obesity effect of lotus leaf extract via brown adipose tissue activation and white fat browning

<i>Nelumbinis</i> folium [Nelumbonaceae; <i>Nelumbo nucifera</i> Gaertn.] is a traditional Chinese medicine. Although studies have reported the efficacy of lotus leaf in weight management, the underlying molecular pathways necessitate further studies. This study aimed to elucidate the effects of lotus leaf on gut microbiota and their metabolites, especially long-chain fatty acids (LCFA), and measure how the effects of lotus leaf on gut microbiota help control obesity. The 12-week Lotus Leaf Extract (LLE) treatment mitigated weight gain, reduced liver and white adipose tissue mass, and activated brown adipose tissue in high-fat diet-induced obese mice, indicating enhanced energy metabolism. LLE reversed gut microbiota dysbiosis by enriching <i>Eubacterium</i> sp. in the gut. Microbiota transplantation indicated that <i>Eubacterium</i> sp. contributes to fat browning and thermogenesis, thereby alleviating host obesity, glucose homeostasis, dyslipidemia, and hepatic steatosis. In addition, <i>Eubacterium</i> sp. significantly increased the levels of margaroleic acid in mouse serum. In summary, the study found that lotus leaf extract can prevent obesity by modulating the gut microbiota, which in turn activates BAT activity and promotes the browning of WAT.