Comparative Effect of Vernonia Amygdalina and Metformin in Alloxan Induced Diabetes Mellitus

Abstract

Metformin is a biguanide and its mechanism of action is exhibited at extra pancreatic level. In clinical practice, it is the first line therapy recommended for newly diagnosed type 2 diabetes mellitus patient (ADA, 2014). Vernonia amygdalina (VA) is a common shrub consumed in Nigeria. This study was done to investigate the comparative effect of VA and metformin in alloxan induced hyperglycaemia in Wistar rats. Twenty five (25) adult Wistar albino rats of both sexes weighing 200-250g were randomly allocated into five (5) groups with 5 rats per group. Group 1 was given normal saline alone without inducing hyperglycaemia to serve as normoglycaemic control, while group 2,3, 4 and 5 were given 6.5mg/100g body weight of alloxan monohydrate to induce hyperglycaemia according to the method of Osikwe et al.,2015, Onahinon et al.,2018. After inducing hyperglycaemia, group 2 were given normal saline, group 3, 10mg/100g body weight of VA, group 4,  20mg/100g body weight of metformin  and group 5, 10mg/100g  body weight of VA and  20mg/100g body weight of metformin for a duration of 2 weeks. Results showed that the fasting blood glucose of group 1 was 81±2.6 mg/dl. The fasting blood glucose of group 2 was 293±6.5 vs 332±17.5mg/dl, group 3 was 304±3.8 vs198±7.4mg/dl, group 4 was 306±7.2 vs 190±4.2mg/dl and group 5 was 310±7.4 vs 155±1.6mg/dl. There was significant difference in the basal fasting blood glucose and fasting blood glucose after group 2,3,4 and 5 were given alloxan (p<0.01). There was significant difference between group 2 and group 3, group 2 and group 4,   and group 2 and group 5 (p<0.01). There was no significant difference between group 3 given VA and group 4 given metformin alone (p>0.05) however, the percentage change in fasting blood glucose in group 3 and 4 after agents were administered were 34.9% and 37.9% respectively. There was a significant difference between group 5 and group 3, and group 5 and group 4 (p<0.01).  This result shows that the antihyperglycaemic effect of VA shows similar efficacy as that of metformin.