Strengthening of antioxidant defense by Azadirachta indica in alloxan-diabetic rat tissues

BACKGROUND: Azadirachta indica has been reported to correct altered glycaemia in diabetes. OBJECTIVE: The aqueous extract of A. indica leaf and bark has been evaluated for its effect on antioxidant status of alloxan diabetic rats and compared with insulin treatment. MATERIALS AND METHODS: The oral effective dose of A. indica leaf (500 mg/kg body weight) and A. indica bark (100 mg/kg body weight) were given once daily for 21 days to separate groups of diabetic rats. At the end of the experimental period blood glucose level and activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G-6-PD), and membrane lipid peroxidation were determined in different fractions of liver and kidney tissues. RESULTS: Diabetic rats showed high blood glucose (P<0.01), increased level of malondialdehyde (P<0.05) and a significant decrease in the activity of antioxidant enzymes. Treatment with insulin, A. indica leaf extract (AILE), and A. indica bark extract (AIBE) restored the above altered parameters close to the control ones. CONCLUSIONS: Both AILE and AIBE were found significantly effective in reducing hyperglycemia-induced oxidative stress. The findings suggest further investigations for the possible use of A. indica as alternative medicine to prevent long-term complications of diabetes.