Background: Chronic hyperglycemia is known to be a high-risk factor for progressive
chronic liver diseases, such as abnormal lipid metabolism. The activation of AMP-activated protein
kinase (AMPK) has a beneficial effect on dyslipidemia. Polyphenols derived from various plants are
involved in AMPK activation.
Objective: We investigated the effects of polyphenol-containing sorghum (Sorghum bicolor) extract
(SE) on plasma lipid metabolism and macrophage infiltration, and measured the expression and
phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) in diabetic rat livers.
Methods: Streptozotocin-induced diabetic rats received 0, 50, or 250 mg/kg of SE orally for 4 weeks.
Blood chemistry, total and phosphorylated protein levels of AMPK and ACC, sterol regulatory element-
binding protein-1c (SREBP-1c) mRNA and protein levels, and macrophage infiltration in the
livers were examined.
Results: Plasma glucose and triacylglycerol levels, which were increased in the untreated diabetic
rats, were significantly lower in the 250 mg/kg SE-treated diabetic rats. AMPK and ACC phosphorylation
levels were significantly increased in the 250 mg/kg SE-treated diabetic rats compared with
those in the untreated rats. There was no difference in the hepatic expression of SREBP-1c between
the diabetic rat groups. Macrophage infiltration in the liver was suppressed by 250 mg/kg of SEtreatment.
Conclusion: These data suggest that SE treatment may affect plasma lipid metabolism and chronic
inflammation by upregulating phosphorylation of AMPK and ACC in diabetic rat livers.