Anti-hyperglycemic effects of Stemonocoleus micranthus (Fabaceae) stem bark on alloxan-induced hyperglycemic rats

Abstract

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=5) were used for all models; group 1 served as the control (received 2 ml/kg of distilled water; p.o.), groups 2, 3, and 4 received S. micranthus extract (SME) 100, 200, and 400 mg/kg, respectively, while group 5 received glibenclamide (GLI 0.2 mg/kg) as a reference 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 and 400 mg/kg) and GLI, respectively. In the OGTT study, suppression in BGC was statistically significant (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 by SME-treatment after 28 days 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.  Key words: Stemonocoleus micranthus, alloxan, glibenclamide, normoglycemia, hyperglycemia.