Studies on the effects of Vernonia amygdalina aqueous leaf extract on the biochemical, haematological and hypoglycemic parameters in diabetic rats: Prerequisite to formulation into pharmaceutical dosage form

Abstract

This study determined the hypoglycaemic effect of Vernonia amygdalina aqueous leaf extract in alloxan induced diabetic rats, as well as its effect on their biochemical and haematological biochemical parameters. Vernonia amygdalina (VA) is a flowering plant and a member of the Asteraceae family with over 200 species. It is a small shrub that grows in tropical Africa. It is commonly called bitter leaf in English because of its bitter taste and is used in Nigeria as both food and medicine. Adult albino rats (36) of both sexes were divided into six groups (1-6). Three fractions (100, 200 and 400 mg/kg) of aqueous leaf extract of VA were obtained and administered to a control group (normal rats) and alloxan induced diabetic rats to check for their hypoglycaemic effects during an experimental period of seven (7) days. The fasting blood sugar levels (FBS) and body weights were monitored using a glucometer and weighing balance, respectively, every 48 hrs. At the end of the 7 days observation, the rats were scarified and the blood was collected for biochemical and haematological analysis. The results showed that the 400 mg/kg body weight dose was most potent as it reduced the fasting blood sugar levels from average of 494.83 mg/dl (2 days after induction) to 81 mg/dl on the 7th day of the experiment. During the same period, the 200 mg/kg body weight dose also reduced the FBS level from 382.33 mg/dl to 98 mg/dl. Also, the 100 mg/kg body weight dose reduced the FBS level after 7 days to 110 mg/dl. The average body weight of the rats decreased from 250.83 g initial weight to 215 g final weight (i.e. 14.28% reduction) compared to the group administered with 200 mg/kg body weight of the extract that reduced from 234.17 g to 206.67 g (11.73% reduction). These doses of the extract (100, 200 and 400 mg/kg) were found to normalize some biochemical parameters such as creatinine, total bilirubin (TB) and high density lipoprotein (HDL). Same doses of the extract were shown to normalize certain haematological parameters such as Red Blood Cell (RBC), Haemoglobin (HGB) and Haematocrit (HCT). However, the effects on the two parameters were more marked with the 400 mg/kg dose. From the above results, Vernonia amygdalina aqueous leaf extract has been found to possess a potent hypoglycaemic activity with significant effects on biochemical and haematological indices of the experimental animals. The results show that this herbal extract which is safe and capables of normalizing biochemical and haematological abnormalities associated with the pathophysiology of diabetes mellitus, can be formulated into acceptable pharmaceutical dosage forms that can be employed in the management of diabetes mellitus.