In vitro Antidiabetic Activity of Crude Ethanol Extracts of Selected Medicinal Plants

Abstract

The incidence of diabetes mellitus has increased globally in the last two decades and there is no cure for it yet. However, several plants have been reported to be used locally for its management. This study was aimed at evaluating the in vitro anti-diabetic activity of the crude ethanol extracts of fourteen (14) medicinal plants used locally for diabetes therapy. This was carried out using non-enzymatic methods (in vitro haemoglobin glycosylation inhibitory assay and in vitro assay of glucose uptake by yeast cells). The highest percentage inhibition of haemoglobin glycosylation (96.68±0.34 %) was observed for crude ethanol extract of Calotropis procera at concentration 20 mg/mL, with no significant difference (p ˃ 0.05) when compared to Anogeissus leiocarpus (95.02±0.22 %), Khaya senegalensis (92.55±1.60 %), Senna occidentalis (92.12±2.48 %), D. microcarpum (91.11±0.38 %) and the standard drug, Acarbose (90.15±0.30 %). The crude ethanol extracts of Balanites aegyptiaca (B. aegyptiaca), Khaya senegalensis, Mangifera indica, Senna podocarpa and the standard drug (metronidazole) had percentage glucose uptake by yeast cells of up to 70 % at the lowest concentration used (0.625 mg/mL) for all the concentrations of glucose tested. However, the highest percentage glucose uptake was observed for ethanol extract of B. aegyptiaca (91.76±0.88 %) at concentration 20 mg/mL, for 20 mM glucose concentration. It could be concluded that ethanol extracts of all the plants used in this study, contain active compounds responsible for inhibiting haemoglobin glycosylation, as well as enhancing the uptake of glucose in yeast cells. As such, some of them with remarkable activity could be standardised and used as herbal remedy for the treatment of diabetes mellitus.