Ameliorative potential of Cortex Lycii on enzymes involved in carbohydrate metabolism in streptozotocin-nicotinamide induced diabetic rats

Cortex Lycii (root back of Lycium chinense) has is a famous traditional Chinese medicine which displays several pharmacological activities including antioxidant and antidiabetic properties. We investigated the effect of the ethyl acetate fraction (QCL) of Cortex Lycii on the enzymes involved in the metabolism of carbohydrate in diabetic rat models. Streptozotocin-nicotinamide (110 and 65mg/kg body weight, respectively) was used to induce diabetes. Diabetic rats were treated with QCL (100, 200 and 400 mg/kg) and glibenclamide (600 μg/kg) daily for six weeks. Upon the completion of treatment, fasting blood glucose (FBG), insulin, glycosylated haemoglobin (HbA1c), haemoglobin (Hb), hexokinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase levels were measured by biochemical assays. Likewise, the body weight, food and water intake was monitored and measured. Diabetic rats displayed significant elevation in the blood glucose, glycosylated hemoglobin and a marked decrease in plasma insulin and hemoglobin. Furthermore, the levels of key enzymes including fructose-1,6-bisphosphatase, glucose-6-phosphatase phosphoenolpyruvate carboxykinase were significantly increased while the activity levels of hexokinase, glucose-6-phosphate dehydrogenase and glycogen were significantly down regulated in diabetic rats. However, treatment of diabetic rats with Cortex Lycii led to a significant reduction the FGB, food and water intake and an increase in the plasma insulin level. Treatment with Cortex Lycii also reversed the altered activity profiles of the key enzymes mentioned above in a dose dependent manner. Our results suggested that Cortex Lycii has a promising therapeutic option in the management of diabetic complications relating to glucose homeostasis and carbohydrate metabolism.