Impact of Vernonia Amygdalina and Gongronema Latifolium Extracts on Insulin and Reproductive Hormones in Diabetic Models

Abstract

The study evaluated the effects of combined extracts of Vernonia amygdalina (VA) and Gongronema latifolium (GL) on the pancreas of streptozotocin (STZ) induced diabetic Wistar rats and on serum concentrations of insulin and reproductive hormonal levels. Thirty-six (36) albino rats were divided equally into 6 groups. Groups A and B which served as normal (NC) and diabetic (DC) controls respectively were only administered placebo. The diabetic test groups C, D, E and F were respectively treated with metformin (5mg/kg b. w.), combined extracts of VA and GL (400mg/kg b. w.), VA (200mg/kg b. w.) and GL (200mg/kg b. w.), for 28 days. Thereafter, the animals were sacrificed; blood and pancreas were collected for serum hormonal assays and histological evaluation, respectively. Changes in animal weights and blood glucose concentrations were also measured within the experimental period. From the results it was observed that the body weight of the animals in both the VA and metformin treatment groups was significantly increased (p<0.05) from -10.5% reduction in the DC, to 10.7% and 23.3% respectively. In the same order, serum glucose levels significantly decreased (p<0.05) by 52.71% and 48.93% in the metformin and combined extract groups respectively. The decrease in other groups was not as remarkable as that of combined extracts group compared to DC which further increased by 64.57%. The extent of reversal of hyperglycemia in the extract treated animals compared well with the metformin treated group. The biochemical results corroborated with results of histological evaluations: The pancreatic β-cells of DC animals which were distorted and degenerated with shrunken cell mass as against prominent islet cells with normal exocrine pancreas of NC animals became rapidly proliferated upon intervention with the combined extracts, suggesting a possible regeneration of the islet cells hence enhanced insulin release which is positively correlated to the observed hypoglycemia and body weight increments . The serum concentration of reproductive hormones of group B animals which was also significantly reduced (p<0.05) compared to group A was markedly improved in all the treatment groups. On the other hand, intervention with metformin did not produce observable differences in the cyto-architecture of the pancreatic islets compared to the diabetic control. For the Feulgen’s reaction, most of the cells in the groups that received the plant extracts were strongly positive suggesting a reversal of DNA damage in these groups.