Abstract
Objectives. Stevia rebaudiana Bertoni leaves are well-known for their sweetness and have been used as a non-caloric sweetener in several countries. It has numerous therapeutic properties which have been proven safe and effective over hundreds of years. In the present study, we aimed to evaluate the possible antioxidant effects of stevia extracts and their role in regulating AMPK in type-1 diabetic rats.
Methods. Fifty male Sprague Dawely rats were divided into: (1) normal control (NC) group; normal rats receiving 0.5 ml normal saline, (2) DM group; diabetic rats receiving 0.5 ml normal saline, (3) DM + MSE group; DM rats receiving 200 mg/kg of methanolic extract of stevia, (4) DM + S group; DM rats receiving 2 mg/kg of pure stevioside, and (5) DM + CGA group; DM rats receiving 10 mg/kg of pure chlorogenic acid. Four weeks after treatment, AMPK activity, GLUT4 mRNA and oxidative stress markers were measured in frozen muscles. Also, fasting blood glucose in serum, insulin and HbA1c were measured at the end of experiment.
Results. DM caused a significant increase in serum fasting glucose, HbA1c and muscle MDA with significant reduction in serum insulin, muscle SOD, catalase, GPx, AMPK activity and GLUT4 expression (p < 0.05). Treatment with stevia extract, pure stevioside and chlorogenic acid caused significant improvements in the studied parameters (p < 0.05).
Conclusions. We concluded that stevia extracts and derivatives may improve metabolic dysfunction in skeletal muscles via upregulation of AMPK and GLUT4 and suppression of oxidative stress.