Alisol A 24-Acetate Prevents Hepatic Steatosis and Metabolic Disorders in HepG2 Cells

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD) is closely associated with metabolic disorders including hepatic lipid accumulation and inflammation. Alisol A 24-acetate, a triterpene from Alismatis rhizome, has multiple biologic activities such as hypolipidemic, anti-inflammatory and anti-diabetic. Thus we hypothesized that Alisol A 24 -acetate would have effect on NAFLD. The present study was conducted to investigate the therapeutic effects and potential mechanisms of Alisol A 24-acetate against hepatic steatosis in a free fatty acids (FFAs) induced NAFLD cell model. Methods: This study was divided into four groups including Control group, Model group (FFA group), Alisol A 24-acetate (FFA+A) group, Fenofibrate (FFA+F) group. Preventive role of Alisol A 24-acetate was evaluated using 10µM Alisol A 24-acetate plus 1 mM FFA (oleate:palmitate=2:1) incubated with HepG2 cells for 24 h, which was determined by Oil Red O Staining, Oil Red O based colorimetric assay and intracellular triglyceride (TG) content. Besides, the inflammatory cytokines tumor necrosis factor (TNF)- α, interleukin (IL)-6 levels as well as the protein and mRNA expressions that were involved in fatty acid synthesis and oxidation including Adiponectin, AMP-activated protein kinase (AMPK) α, peroxisome proliferator-activated receptor (PPAR) α, sterol regulatory element binding protein 1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), carnitine palmitoyltransferase 1 (CPT1) and acyl coenzyme A oxidase 1 (ACOX1) were detected. Results: Alisol A 24-acetate significantly decreased the numbers of lipid droplets, Oil Red O lipid content, and intracellular TG content. Besides, inflammatory cytokines TNF-α, IL-6 levels were markedly inhibited by Alisol A 24-acetate. Furthermore, Alisol A 24-acetate effectively increased the protein and mRNA expressions of Adiponectin, the phosphorylation of AMPKα, CPT1 and ACOX1, whereas decreased SREBP-1c, the phosphorylation of ACC and FAS at both protein and mRNA levels. However, there was no significant effect on the protein and mRNA expressions of PPARα by Alisol A 24-acetate. Conclusions: These results demonstrated that Alisol A 24-acetate effectively ameliorated hepatic steatosis likely through Adiponectin, which activated AMPKα signaling pathways via down-regulating SREBP-1c, ACC, FAS and up-regulating CPT1 and ACOX1, and inhibited inflammation. Thereby, Alisol A 24-acetate could be a promising candidate for the treatment of NAFLD.