This study evaluated the anti-hyperglycemic potential of Stemonocoleus micranthus Harms. (Fabaceae) stem bark.Three models used in this study were: normoglycemic animal model, oral glucose tolerance test (OGTT) and alloxan-induced hyperglycemic model for acute and prolonged administration. Five (5) groups of rats (n=6) were used for all models; group 1 served as the control while groups 2, 3, and 4 received S. micranthus extract (SME; 100, 200, and 400 mg/kg), respectively. Glibenclamide (GLI 0.2 mg/kg) was used as a reference standard drug. In the normoglycemic study, the % reduction in blood glucose concentration (BGC) was 22.24, 29.97, 30.03 and 37.28% for SME (100, 200, 400 mg/kg) and GLI, respectively. In the OGTT study, suppression in BGC was statisticallysignificant(p < 0.05) at 120 min for the 400 mg/kg SME group. The glycemic changes (%) observed in SME (100, 200 and 400 mg/kg) treated rats were 3.4%, 0.86% and 0.45%, respectively at the 120 min relative to 0 min values. Also, oral administration of SME (100, 200, 400 mg/kg) and GLI significantly (p<0.05) reduced the BGC to varying degrees in alloxan-induced hyperglycemic rats. The SME at 400 mg/kg produced the highest percentage diminution in BGC of 23.26% and 67.66% for the acute and the prolonged anti-hyperglycemic study respectively, whereas the standard drug, GLI, exhibited 73.55% and 66.10%, respectively. Histopathological studies revealed protection from the harmful effect of alloxan on the kidney and liver of SME-treated hyperglycemic rats after 28 days of treatment as against GLI treated group where there was evidence of mild hepatosis. From the results, it can be deduced that S. micranthus stem bark possesses anti-hyperglycemic effects, thus scientifically corroborating with the folkloric use.
Keywords: Stemonocoleus micranthus, alloxan, glibenclamide, normoglycemia, hyperglycemia.