Modulatory effects of fisetin, a bioflavonoid, on hyperglycemia by attenuating the key enzymes of carbohydrate metabolism in hepatic and renal tissues in streptozotocin-induced diabetic rats

Fisetin (3, 7, 3′, 4′-tetrahydroxyflavone) is a bioflavonoid found in fruits and vegetables. It exhibits a wide variety of pharmacological properties, including antioxidant, antiinflammatory and anticarcinogenic effects. Recently we have reported the hypoglycemic actions of fisetin. Oral administration of fisetin (10 mg/kg body weight) to diabetic rats for 30 days established a significant (P < 0.05) decline in blood glucose and glycosylated hemoglobin levels and a significant (P < 0.05) increase in plasma insulin level. In the present study the activities of key enzymes of carbohydrate metabolism were assayed to establish the modulatory actions of fisetin in maintaining the glucose homeostasis. The altered activities of key enzymes of carbohydrate metabolism such as hexokinase, pyruvate kinase, lactate dehydrogenase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, glucose-6-phosphate dehydrogenase, glycogen synthase and glycogen phosphorylase in liver and kidney tissues of diabetic rats were significantly (P < 0.05) reverted to near normalcy by the administration of fisetin. Thus, fisetin regulates carbohydrate metabolism by modulating the key regulatory enzymes in the hepatic and renal tissues of diabetic rats.