Antihyperglycemic effect of 18β-glycyrrhetinic acid, aglycone of glycyrrhizin, on streptozotocin-diabetic rats

The study was designed to investigate the antihyperglycemic effect of 18β-glycyrrhetinic acid, aglycone of glycyrrhizin, on streptozotocin-diabetic rats. Diabetes was induced in adult male albino rats of the Wistar strain, weighing 180–200 g, by administration of streptozotocin (40 mg/kg of body weight) intraperitoneally. Diabetic rats showed increase of plasma glucose and glycosylated haemoglobin (HbA1c) and a decrease of plasma insulin and haemoglobin (Hb). Activities of gluconeogenic enzymes such as glucose 6-phosphatase, fructose 1, 6-bisphosphatase increased and glucokinase, glucose 6-phosphate dehydrogenase decreased in the liver along with glycogen. Oral administration of 18β-glycyrrhetinic acid (50, 100, or 200 mg/kg/body weight) or glibenclamide (600 µg/kg/body weight) in 5% dimethyl sulfoxide, for 45 days, prevented the above changes and improved towards normalcy. No significant effect was observed in normal rats treated with 18β-glycyrrhetinic acid (200 mg/kg/body weight). Thus, our results show that 18β-glycyrrhetinic acid at 100 mg/kg of body weight possesses a potential antihyperglycemic effect that is comparable with glibenclamide.