oa Hypoglycemic and Cardioprotective Effects of Methanol Extracts of Gymnema Sylvestre Plant and Annona Senegalensis Carpels Used in the Folkloric Treatment of Diabetes

The epidemic of diabetes has major health and socioeconomic impacts especially in developing countries, and subjects with diabetes have increased risk of disease affecting the heart, blood vessels, eyes, kidneys and nerves. Whole Gymnema sylvestre plant and Annona senegalensis carpels are used in the folkloric treatment of diabetes mellitus and the management of its attendant complications. Diabetes was induced in Swiss albino rats by single intraperitoneal administration of 11  mg/kg bodyweight of alloxan monohydrate and rats with blood glucose ≥  206 mg/dl were considered diabetic. Rats in their respective groups were orally administered 100, 300 and 600 mg/kg bodyweight of extracts of either Annona senegalensis carpels or Gymnema sylvestre daily for fourteen days while the standard drug group received 100 mg/kg bodyweight of metformin for the same period. The normoglycaemic (positive control) and the diabetic untreated (negative control) groups received 0.5 ml normal saline. The animals were euthanized on the 15th day and blood samples were collected by carotid puncture for biochemical analysis. The 600 mg/kg bodyweight dose of Gymnema sylvestre and 300 mg/kg bodyweight dose of Annona senegalensis carpels respectively reduced the blood glucose of diabetic rats by 76.45 % and 72.01 %. All treatment groups of Gymnema sylvestre gave urea and creatinine values that showed no significance differences (p>0.05) with the normoglycemic (positive control) group while urea and potassium ion (K+) concentrations at 600 mg/kg bodyweight of Annona senegalensis carpels extract reduced significantly as the blood glucose progressively declined. Chloride ion (Cl⁻ ) concentrations in the treatment groups for both extracts did not differ from the normoglycemic (control) group, while there was a reduction in the concentrations of potassium ion (K⁻ ) of 100 and 300 mg/kg bodyweight treated groups of Gymnema sylvestre extract. There was also a reduction in the concentration of sodium in all treated groups when compared with the normoglycemic group. The concentrations of total cholesterol, triacylglycerol, low density lipoprotein also reduced regressively as the treatment days progressed and a concomitant increase in the values of high density lipoprotein in all treated groups for both extracts when compared with diabetic untreated (negative control). The crude methanol extracts of Gymnema sylvestre and Annona senegalensis carpels were able to lower the blood glucose of diabetic rats and ameliorate the attendant hyperlipidemic effect associated with diabetes.