Dual beneficial effects of naked barley “Betaone” extract on high-fat diet/streptozotocin-induced hyperglycemia and hepatosteatosis in mice

Abstract This study examined the beneficial effects of a newly developed naked barley “Betaone” extract in high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice. Betaone has a higher β-glucan content than conventional barley “Waxy”. Although the anti-diabetic property of barley β-glucan is well known, its phytochemical role is unclear. In this study, the anti-diabetic effects of a Betaone prethanol extract (BE) with a high phytochemical content were analyzed. The diabetic mice were divided into four groups: diabetic control (DC), two doses of BE (200 or 500 mg/kg/day), and positive control Psidium guajava L. leaves extract (GV, 200 mg/kg/day). After six weeks, BE significantly lowered the fasting blood glucose level and improved the insulin tolerance compared to the DC. Immunohistochemistry staining showed that the BE increased the insulin expression compared to the DC. BE up-regulated the levels of glycogen synthesis (GYS2 and UGP2) and glycolysis-related mRNA (GK, PFK1, and PK), whereas it down-regulated those of gluconeogenesis-related mRNA (G6Pase, FBP1, and PEPCK) in the liver. The changes in the GV group were similar. BE decreased the serum free fatty acid levels and hepatic lipid accumulation (triglyceride, cholesterol, and lipid droplet) significantly compared to the DC. These changes of BE were attributed to the suppression of lipogenesis and the stimulation of fatty acid oxidation in the gene expression. These results suggest that BE has dual beneficial effects on hyperglycemia and hepatosteatosis in HFD/STZ-induced T2DM mice by modifying the hepatic glucose and lipid metabolism.