Effect of Alkaloid-rich Fraction of Dacryodes edulis Leaves on the Cytoachitecture of the Liver and Blood Glucose Levels in Streptozotocin-Induced Hyperglycemic Rats

Abstract

Introduction: Diabetes mellitus is a chronic disease characterized by hyperglycemia due to insufficient insulin production or action. Numerous medicinal plants have been known for their anti-diabetic effects and Dacryodes edulis is one of them. Its extracts have been known for their medicinal qualities as it has been used to treat or manage many illnesses including diabetes. This is made possible due to the pharmacological properties of its bio-constituents constituents. Aims: In this study, the ameliorative potential of an alkaloid-rich fraction of Dacryodes edulis leaves was investigated on the liver of hyperglycemic adult Wistar rats. The objectives were to determine its effects on liver histology and blood glucose level. Methods: Thirty-seven (37) rats weighing between 140-190g were used for the research. Twelve (12) rats were used for its acute toxicity study, while twenty-five (25) rats were grouped into five. The groups were labelled A to E and contained five rats each. Group A (normal control) rats were given food pellets and distilled water only. Group B (diabetic control) rats were given 60mg/kg BW of streptozotocin. Group C rats were given 60mg/kg BW of streptozotocin + 500mg/kg BW of Dacryodes edulis extract, while Group D rats were given 60mg/kg BW of streptozotocin + 1,000mg/kg BW of Dacryodes edulis extract. Group E served as the metformin treated group and were given 60mg/kg BW of streptozotocin + 50mg/kg BW of metformin. The administration of streptozotocin and metformin were through the intraperitoneal route, while that of Dacryodes edulis extract was through the oral route with the aid of an oral gavage. The administration lasted for twenty-eight (28) days, after which the rats were made to fast overnight with access to only water. The rats were then weighed and then anaesthetized. Whole blood was collected through cardiac puncture and liver tissue obtained for histological analysis. Results: The results showed degenerating liver histology with hepatocytes showing pyknotic nuclei, mild dilation of sinusoids, inflammatory cells and dilation of the central vein in the diabetic group as compared to the normal control group which showed a normal liver histology, with hepatocytes having abundant cytoplasm and prominent nuclei, well out-lined sinusoids and an intact central vein. The metformin group displayed mild degenerative changes compared to that of group B rats. The high dose extract group D showed a preserved cytoarchitecture of the liver, while the low dose extract group C displayed mild degenerative changes. A significant decrease (p<0.05) in the fasting blood glucose level was observed in the metformin and extract treated groups compared to the diabetic group (p<0.05). This shows that Dacryodes edulis alkaloid extract possesses hepato-protective properties and a strong anti-diabetic potential, thereby making it useful in the management of diabetes mellitus and its complications. Conclusion: The alkaloid-rich fraction of Dacryodes edulis leaves can be considered as an alternative drug in the management of diabetes mellitus.