Ameliorative Effect of Curcuma longa Ethanolic Extract on the Histology, Hepatic Glycogen Content and Some Biochemical Parameters of the Liver in Streptozotocin-Induced Hyperglycemic Wistar Rats

Introduction: Diabetes mellitus is a life threatening disease that requires immediate medical treatment. Numerous medicinal plants have been known for their anti-diabetic effects and Curcuma longa (turmeric) is one of them. This attribute is possible due to the pharmacological properties of its bio-constituents. In this study, the ameliorative potential of ethanolic extract of Curcuma longa was investigated on the liver of hyperglycemic adult Wistar rats. The objectives were to determine its effects on liver histology, hepatic glycogen content and some liver biochemical parameters.

Methods: Forty (40) rats weighing between 120-180g were used for the research. Sixteen (16) rats were used for its acute toxicity study, while twenty-four (24) rats were grouped into four. The groups were labelled A to D and contained six rats each. Group A (normal control) rats were given food pellets and distilled water only. Group B (diabetic control) rats were given 65mg/kg BW of streptozotocin IP. Group C served as the standard group and was given 65mg/kg of streptozotocin IP + 250mg/kg of metformin IP, while Group D (test group) rats were given 65mg/kg BW of streptozotocin IP + 500mg/kg of Curcuma longa extract. Curcuma longa extract was administered 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 anaesthetized and whole blood obtained through cardiac puncture for biochemical analysis. Liver tissue was obtained for histological and glycogen content analyses.

Results: The results showed severe destruction of hepatocytes with widely spread cytoplasmic vacuolation, loss of hepatic lobules and hepatic inflammation in the diabetic group, whereas it showed prominent nuclei, hepatocytes and distinct sinusoidal spaces in the normal control group. The metformin group showed an intact architecture of the liver tissue with indicating regeneration in the liver, while the Curcuma longa extract group showed a preserved liver cytoarchitecture. There was a significant decrease (p<0.05) in the fasting blood glucose level and liver enzyme activities in the standard and test groups compared to the diabetic group (p<0.05). There was also improvement in glycogen content of the standard and test groups in comparison with the diabetic group (p<0.05).

Conclusion: Curcuma longa possesses hepato-protective properties and a strong anti-diabetic potential, therefore it can be considered as an alternative drug in the management of diabetes mellitus and its complications.