Objective: The present investigation was undertaken to explore the possible mechanisms of Plectranthus amboinicus leaf extract in alloxan-induced diabetic rats.
Materials and methods: Control and alloxan-induced diabetic albino rats received different treatments; orally control (vehicle), 200 mg/kg and 400 mg/kg of ethanol extract of Plectranthus amboinicus (PAEE) and 600 μg/kg of glibenclamide (standard) for 15 days. At the end of the experiment, the animals were sacrificed and enzyme activities of carbohydrate metabolism were measured in the liver.
Results: Diabetic control rats showed a significant elevation (P < 0.001) in fasting blood glucose on successive days of the experiment as compared with their basal values, which was maintained over a period of 2 weeks. Daily oral treatment with PAEE showed a significant reduction (P < 0.001) in the blood glucose levels on successive days of the experiment as compared with their basal values. The most pronounced antihyperglycemic effect was obtained with the dose of 400 mg/kg. PAEE shows a dose-dependent reduction in gluconeogenic enzymes like glucose-6-phosphatase and fructose-1,6-disphosphatase. After 15 days of treatment with PAEE, glycolytic enzymes like phosphoglucoisomerase resulted in a significant increase with a concomitant significant decrease in the activities of aldolase. On the other hand, glucose-6-phosphate dehydrogenase was significantly improved in diabetic rats on administration of PAEE; the 400 mg/kg dose of PAEE elicited a more potent effect compared with the 200 mg/kg dose.
Conclusion: The results obtained in this study provide evidence of the antidiabetic activity of PAEE, mediated through the regulation of carbohydrate metabolic enzyme activities.
Keywords: Aldolase; Plectranthus amboinicus; alloxan; glucose-6-phosphate dehydrogenase.