Inhibition of Microsomal Lipid Peroxidation and Protein Oxidation by Carica papaya (L) Leaf against Carbon Tetrachloride-Induced Hepatic Injury in Wistar Albino Rats

Aims: To investigate the hepatoprotective activities of C. papaya leaf in Carbon tetrachloride induced hepatic damage in albino rats.

Place and Duration of Study: Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, Niger Delta University, Wilberforce Island, Amassoma, Bayelsa-State, Nigeria, between April 2009 through July 2009.

Methods: Activity of total protein and bilirubin (direct and indirect bilirubin) in the serum were determined colourimetrically, while lipid peroxidation products, malondialdehyde (MDA), were measured in liver homogenate. Histopathological studies of the liver in both pretreated rats and controls were also, carried out. Group 1 (negative control) were fed with 100% rat feed. Groups 2- 4 were pretreated with 10, 30 and 50% C. papaya leaf respectively, while Group 5 (normal control) received 100% rat feed. Rats in Groups (1-4), were injected with CCl4 (0.5 ml/kg body weight in 0.5 ml olive oil) on the 29th day while rats in group 5 were not administered with CCl4 (normal control). The results were statistically analyzed using one-way analysis of variance (ANOVA).

Results: There was significant increase (p< 0.05) in the levels of malondialdehyde (MDA) and bilirubin (direct and indirect) in rats Group 1 when compared with the normal control. However, there is a significant decrease in the levels of these biochemical parameters (malondialdehyde and bilirubin) in the pretreated Groups (2-4) when compared with the negative control. Also, the protein levels significantly decreased (p< 0.05) in the untreated rat Group 1 when compared the normal control. Pretreatment with C. papaya leaf significantly increased the levels of total protein in the rat Groups (2-4) when compared with the untreated Group 1. The decrease in the levels of MDA and bilirubin in the pretreated groups were concentration dependent. Rats in Group 4 that pretreated with 50% C. papaya leaf had the lowest values for MDA and bilirubin. Histopathology of the liver showed reduced level of injury with normal architecture in pretreated rats while; those not pretreated were presented with severe degrees of injuries.

Conclusion: Conclusively, the study reveals that Carica papaya may confer hepatoprotectivty to the rats exposed to carbon tetrachloride-induced liver damage.