Antidiabetic activity and safety evaluation of two Cameroonian medicinal plants in Streptozotocin-rat model: Tetrapleura tetraptera (Fabaceae) and Irvingiagabonensis (Irvingiaceae)

Background: Irvingia gabonensis and Tetrapleura tetraptera are widely employed by traditional healers of the southern regions of Cameroon to treat diabetes. However. there is only limited or no scientific evidence on the real potential of these two medicinal plants to serve as alternative therapies. The present works thus aimed to evaluate the antidiabetic activity of the barks of I. gabonensis and fruits of T. tetraptera. Methods: The antidiabetic potential of the four extracts was assessed by evaluating the hypoglycaemic activity through the oral glucose tolerance test (OGTT) in male Wistar albino rats and the subacute antidiabetic assay in streptozotocin-induced Wistar rat model. For the later. clinical markers (water and food intake, urine excretion), Fasting Blood Sugar FBS), the effects on some vital organs (liver and kidney), and lipid profile were considered. Safety was evaluated using the in vivo acute toxicity test in mouse model. Results: Out of the four extracts prepared from T. tetraptera and I. gabonensis, and tested for their antidiabetic potential, only the hydroethanol extract of the stem bark of I. gabonensis showed promising hypoglycemic and anti-hyperglycemic activity from preliminary screening. Of the two doses of this extract considered for the subacute antidiabetic assessment, the dose of 500mg/Kg demonstrated the highest activity reflected in significant improvement in both clinical and biochemical markers with a 100% recovery rate after 21 days treatment of the STZ-induced diabetic Wistar rats. At this dose, the I. gabonensis extract was shown to also improve liver and kidney functions as well as mitigating dyslipidemia in diabetic rats. Overall, its pharmacological properties were above those of the reference drug metformin at 10mg/Kg dose. More interestingly, the acute toxicity study revealed a relative safety of this extract in mice. Conclusion: The present work confirms the potential of the hydroethanolic extract of I. gabonensis to serve a source of new antidiabetic drugs. Further investigations are therefore envisaged.