RESUMO
OBJECTIVES: Researchers all over the world are exploring herbal supplements to control diabetes and its complications. This study evaluated the antidiabetic action of Morus rubra L. aqueous leaf extract through its effect on hyperglycaemia, dyslipidaemia and oxidative stress in streptozotocin-induced diabetic rats. METHODS: The extract was orally administered to diabetic rats (100, 200 and 400 mg/kg body weight) daily for 21 days. Fasting blood glucose was measured on days 0, 7, 14 and 21. At the end of the experiment, blood samples were drawn to measure glucose tolerance, glycosylated haemoglobin, insulin, C-peptide and lipid parameters. Antioxidant enzymes (superoxide dismutase and catalase), reduced glutathione and lipid peroxides were determined in blood and liver tissue. Histopathological examination of pancreatic tissue was also performed. KEY FINDINGS: The extract showed a dose-dependent fall in fasting blood glucose. Treatment with 400 mg/kg extract produced a significant reduction in glycosylated haemoglobin with a concomitant elevation in plasma insulin and C-peptide levels. The altered serum lipids in diabetic rats were significantly restored following treatment with the extract. In erythrocytes, as well as liver, the activity of antioxidant enzymes and content of reduced glutathione were found to be significantly enhanced, while levels of serum and hepatic lipid peroxides were suppressed in extract-fed diabetic rats. Histopathological examination of pancreatic tissue revealed an increased number of islets and beta-cells in extract-treated diabetic rats. CONCLUSIONS: M. rubra aqueous leaf extract leads to control over hyperglycaemia and dyslipidaemia. The study also demonstrates its antioxidant nature, and hence it may be protective against diabetic complications.
