Purpose: To investigate anti-diabetic effect of the ethanol leaf extract of Newbouldia laevis (P. Beauv) in alloxan-induced diabetic rats.

Methods: Alloxan (150 mg/kg) was administered to wistar albino rats via the intraperitoneal route. The diabetic rats were then placed in 5 groups, following stabilization of hyperglycemia. The first group was untreated, the next three groups received, each day, 100, 200 and 400 mg/kg body weight of the ethanol extract Newbouldia laevis and the fifth group received a reference standard, glibenclamide (5 mg/kg). Treatment was via the oral route for 14 days and fasting blood sugar level was monitored over this period. Acute toxicity (oral and intraperitoneal) studies on the extract was carried out, as well as phytochemical screening of the extract.

Results: All doses of the extract (100, 200, and 400 mg/kg) significantly (p < 0.05, p < 0.0001, p <0.05, respectively) lowered fasting blood glucose level, notably at the 4^th, 8^th and 14^th day. Glibenclamide (5 mg /kg) also significantly lowered fasting blood glucose (p < 0.0001). The results on acute toxicity revealed that for the oral and intraperitoneal route, mortality was  at 8 and 1 g/kg, respectively while LD₅₀ was 6 g/kg, indicating the high safety status of the plant. Phytochemical screening revealed the presence of saponins, tannins, alkaloids and flavonoids.  

Conclusion: This study supports the use of Newboulda laevis in traditional medicine as well as highlights the need to further explore the potentials of the plant extract as a antihyperglycemic agent.