Effect of Hordeum vulgare L. (Barley) on blood glucose levels of normal and STZ-induced diabetic rats

Barley (Hordeum vulgare L.) is the world's fourth most important cereal crop after wheat, rice and maize. It is readily available with reasonable cost, and has the highest amount of dietary fiber among the cereals which may be beneficial for metabolic syndrome. In the present study, the effect of hydroalcoholic extract of barley seeds and a protein enriched fraction on blood glucose of normal and streptozotocin (STZ)-induced diabetic rats (STZ, 55 mg/kg, i.p) were investigated. Normal and diabetic male Wistar rats were treated daily with normal saline ( 1 ml), barley hydroalcoholic extract (BHE) (0.1, 0.25, 0.5 g/kg), protein enriched fraction (PEF) (0.1, 0.2, 0.4 g/kg) and glibenclamide (1 and 3 mg/kg), separately and the treatment was continued for 11 days. Blood samples were taken at 0, 1, 2, 3, 9 h in the first day and the days 5 (120 h) and 11 (264 h) for measuring the blood glucose levels (BGL). Our results indicated that none of the BHE and PEF, were effective to reduce BGL in normal or diabetic rats in acute phase of treatment (1st day). Nevertheless, BHE at doses of 0.25 and 0.5 g/kg, were only effective in detracting BGL of diabetic rats after 11 days of continued daily therapy. Moreover, BHE restored body weight of diabetic rats at the end of treatment. Glibenclamide had also hypoglycemic action in normal and diabetic rats after both acute and extended treatments. These findings suggest that barley seeds hydroalcoholic extract, has a role in diabetic control in long term consumption, and this effect might be at least due to its high fiber content. More detailed studies are warranted to demonstrate its mechanism of action and identify active components.