Antidiabetic Potential of Methanolic Extract of Newbouldia laevis (Ogirisi) Leaves in Hyperglycemic Wistar Rats

Ideal management of prolonged hyperglycaemia presents both micro and macro vascular complications, a leading cause of morbidity and mortality in diabetic subjects. This study was under taken to give credence to the traditional use of Newbouldia laevis (Ogirisi) leaves in the treatment of diabetes mellitus (DM). Alloxan monohydrate (140 mg/kg) was administered to male wistar rats via the intra-peritoneal route. The oral LD50 of the methanoic extract of N. laevis was >1200 mg/kg. The normal male rats were placed in Group A-Negative control group and the diabetic male wistar rats were then placed in 5 groups following stabilization of hyperglycemia. The diabetic groups include Group B–positive control was untreated, Group C received a standard drug, Gluformin (5 mg/kg) and the last three groups (Group D, E, F) received low dose 200 mg/kg, middle dose 400 mg/kg, high dose 800 mg/kg respectively of the methanolic N. Laevis extract. Treatment was via the oral route for 2 weeks and fasting blood sugar level was monitored over this period. Phytochemical screening revealed the presence of glycosides, phenolic, polyphenol and abundant flavonoids. Notably, at the 2nd week of treatment, the three doses (200 mg/kg, 400 mg/kg and 800 mg/kg) of the methanolic extract of N. laevis leaves administered significantly (P<0.05) lowered fasting blood glucose levels. Gluformin also significantly lowered fasting blood glucose (P<0.05). These findings suggest that methanolic extract of N. laevis leaves possesses antihyperglycaemic activities and can be used in folk medicine for the management of diabetes mellitus. Hence, it could be considered for further in vivo evaluation.