Barley sprout extracts reduce hepatic lipid accumulation in ethanol-fed mice by activating hepatic AMP-activated protein kinase

Abstract

Chronic alcohol consumption leads to hepatic lipid accumulation and alcoholic fatty liver disease. Previously, we demonstrated that barley sprout extract, which contains saponarin as an active compound, reduces hepatic steatosis. In this study, we investigated the effect of barley sprout extracts (BSE) on hepatic lipid accumulation in a mouse model of alcoholic fatty liver disease. Seven-week-old C57BL/6 mice were fed an alcohol-containing diet (5% ethanol) and a low or high dose of BSE (100 or 200mg/kg body weight, respectively) for 10days. The high dose of BSE significantly decreased hepatic lipid accumulation compared with the ethanol-only control group. In the second animal study, mice were fed an alcohol-containing diet for 10days, followed by a 45% high-fat diet with oral administration of BSE (100 or 200mg/day/kg body weight) for 4weeks. Mice in both BSE-fed groups showed reduced hepatic steatosis. In the livers of mice fed BSE, phosphorylation of AMP-activated protein kinase (AMPK) was increased, and expression of hepatic autophagy markers was elevated. In cultured hepatocytes, BSE (200μg/mL) increased the rate of fatty acid oxidation and reduced that of fatty acid synthesis. Taken together, these findings suggest that BSE promotes degradation of lipid droplets and subsequent activation of fat oxidation by activating AMPK in the liver, thus protecting against development of hepatic steatosis in alcohol-fed mice. Saponarin, a major flavonoid in BSE and an activator of AMPK, increased the activity of microsomal triglyceride transfer protein, which suggests that the reduction in hepatic triglyceride levels was mediated by this component of BSE. In conclusion, BSE ameliorated hepatic steatosis in a mouse model of ethanol-induced fatty liver by activating AMPK, an effect possibly mediated by the saponarin component.