The Hypolipidemic and Hypoglycemic Activities of Fermented Brown Rice Fibers by Regulating PPARα and ChREBP in the Livers of C57BL/6J Mice

Abstract

The fermentation of brown rice produces black vinegar that has been suggested with beneficial metabolic effects; however, the mechanisms of actions of fermented brown rice have not been studied. We found that fermented brown rice extracts, especially a fraction of fermented brown rice fibers (FBRF), exhibited hypolipidemic and hypoglycemic activities in vivo. The oral administration of FBRF to C57BL/6J mice reduced plasma cholesterol, triglycerides, lowdensity-lipoprotein cholesterol levels, hepatic lipid accumulation and adipocyte size. The activation and induction of hepatic PPARα and subsequent regulation of its target gene expressions in fatty acid uptake and oxidation were the major mechanism for reducing plasma and hepatic triglyceride concentrations. In addition, FBRF improved glucose tolerance and insulin sensitivity. FBRF feeding reduced the expressions of hepatic ChREBP, a key transcription factor in gluconeogenesis, and pro-inflammatory cytokines, thus improved insulin resistance. These results demonstrated that FBR, especially FBRF, shows potent hypolipidemic and anti-diabetic activities through regulating the expression of genes associated with lipid, glucose metabolism and inflammatory cytokines.