We investigated the effects of a Leonurus japonicus ethanol extract (LJE) on nonalcoholic fatty liver disease (NAFLD). An in vitro model of hepatic steatosis was treated with 1 mM free fatty acid (FFA) in HepG2 cells. An in vivo NAFLD model was established using C57BL/6 mice fed a high-fat diet (HFD) and administered LJE (100 or 200 mg/kg) orally for 14 weeks. LJE treatment suppressed lipid accumulation and intracellular triglyceride levels significantly in a concentration-dependent manner in HepG2 cells. Moreover, LJE significantly reduced the expression of sterol regulatory element binding protein 1-c, and its downstream genes, which are associated with lipogenesis, in HepG2 cells. In HFD-fed mice, LJE treatment decreased body weight significantly and decreased serum alanine transaminase levels to normal values, concurrent with a decrease in hepatic lipid accumulation. Furthermore, LJE supplementation ameliorated insulin sensitivity by decreasing serum glucose and insulin levels. LJE improved hepatic steatosis by increasing the expression of phosphorylated AMP-activated protein kinase and peroxisome proliferator-activated receptor-α in HFD-fed mice and FFA-treated HepG2 cells. The results suggested that LJE might be a potential therapeutic agent to treat NAFLD.
Keywords: HepG2 cells; Leonurus japonicus; free fatty acids; high-fat diet; nonalcoholic fatty liver disease; obesity.