Glucose Tolerance Test in Hyperglycemic Guinea Pigs Treated with Aqueous Vernonia Amygdalina

We have determined the comparative response in hyperglycemic guinea pigs to a glucose tolerance test (GTT) following treatment with either unboiled or boiled aqueous extract of Vernonia amygdalina (bitter leaf ) or glucophage solution. The animals were divided into four groups, fasted overnight and each received glucose solution by intraperitoneal injection (ip.) following fasting to induce hyperglycemia. One group served as control, the second group received unboiled extract of bitter leaf, the third group received boiled extract of bitter leaf, while the fourth group received a glucophage solution all by i.p. Following treatment, blood samples were collected from each group at 30 min, 60min, and 180 min and glucose concentration was determined in each sample by the glucose oxidase method.
The results show that at 30 min, control blood glucose level spiked to 17.4 mmol/L from a Fasting Blood Glucose level of 5.6mmol/L; at 60 min, the level dropped to 8.1 mmol/L and then stabilized to Fasting (Baseline) level of 5.5 mmo/L at 180min. This curve (pattern) is consistent with classical GTT protocol. In the GTT pattern of animals treated with unboiled aqueous bitter leaf extract (b.l.e), blood glucose level rose to 9.8 mmol/L at 30min, nose dived to 5.7 mmol/L at 60min (a Baseline value), and stabilized at 5.6mmol/L after 180min. On the other hand, in the GTT pattern of the boiled aqueous b.l.e. and glucophage solution, excess blood glucose was not cleared to Baseline (control) level even after 180 min: for boiled b.l.e, blood glucose level rose to 12.9 mmol/L at 30 min, dropped to 6.7 mmol/L and stabilized at 6.2 mmol/L at 180 min, a level higher than baseline. Similarly, for glucophage, a spike of blood glucose level of 13.1 mmol/L occurred at 30 mins, (near identical with boiled b.l.e), dropped to 7.2 at 60 min (higher than unboiled b.l.e) and increased to 9.5 mmol/L after 180 min (similar pattern to boiled b.l.e).
These results clearly show that under these GTT conditions, the unboiled water b.l.e. cleared the excess blood glucose molecules more rapidly and more quantitatively than either the boiled water b.l.e. or glucophage, and therefore may be a more effective antihyperglycemic preparation.