In vivo assessment of antidiabetic activity and safety of polyherbal teas from selected Cameroonian medicinal plants: Persea americana, Ageratum conyzoides and Mangifera indica

Background: Diabetes mellitus (DM) is a metabolic disorder of the endocrine system which results in persistently high blood glucose levels. Available control measures do not completely cure the disease and most patients in the tropics cannot afford diabetes drugs regularly. Amongst other plants, Mangifera indica (MI), Persea americana (PA), and Ageratum conyzoides (AC) are used individually as traditional medicine by most people for the management of diabetes. This work was set to produce polyherbal teas (water infusion) from these plants and evaluate in vivo antidiabetic activity and safety of the teas. Methods: Three (3) monoherbal teas (MI, PA, AC) and 4 polyherbal of which 3 composed of two plants each (MI+PA, MI+AC, PA+AC) and one including all the plants (MI+PA+AC) were formulated. The antidiabetic activity was assessed by evaluating the hypoglycaemic activity of the teas by carrying out the oral glucose tolerance test (OGTT) in male Wistar albino rats and the subacute antidiabetic assay in streptozotocin-induced diabetic rats. Safety was evaluated using the in vivo acute toxicity test in mouse model. Results: The OGTT revealed a significant drop in post-prandial glucose peak in rats treated with 20mg/kg monoherbal tea from Mangifera indica leaf (MI), as compared to the negative control (distilled water). The polyherbal tea of all three plants (AC+MI+PA) at a dose of 20mg/kg was able to return the glucose levels to normal 30mins after the glucose peak. The tea AC+MI+PA also exhibited a higher antidiabetic activity as it produced a 60% glycemia recovery rate compared to the reference drug glibenclamide and monoherbal tea MI with 40% and 20% recovery rate respectively. Polyherbal tea and MI exhibited hepato-protective and nephron-protective activities. The in vivo acute toxicity test showed that the teas were not toxic as there was no record of mortality and adverse effects in physical appearance, behavior, change in body weight, water, and food intake. Conclusion: Out of the seven teas produced, two showed promising antidiabetic potential, with both acute hypoglycemic effects and significant subacute efficacy. Further investigations are envisaged to pursue the development of improved alternative therapies from these, to address the enduring challenge of diabetes, particularly in resource-limited settings. Keywords: Diabetes mellitus; antidiabetic; activity; polyherbal tea.