Ameliorative Effect of Natural Cocoa on Hepatic Injury Caused by Overdose of Paracetamol in Rats

Abstract

Introduction: Paracetamol (acetaminophen) is a widely used over-the-counter analgesic and antipyretic drug which is known to cause liver injuries in both humans and experimental animals when administered in overdose. Supratherapeutic dose of paracetamol results in accumulation of reactive oxygen species (ROS) which impairs the antioxidants defence mechanisms and thus, causes a redox imbalance. The resulting oxidative stress plays a vital role in paracetamol-induced hepatic toxicity. Current well-known intervention for paracetamol toxicity involves the administration of N-acetyl cysteine (NAC) which serves as a glutathione precursor. Cocoa flavanols have antioxidant properties, and hence potential to mitigate the effect of oxidative stress caused by paracetamol overdose and concomitant tissue damage. Aim: To investigate the ameliorative activity of natural cocoa in paracetamol-induced hepatotoxicity in rats. Methodology: 20 male Sprague Dawley rats were weighed and randomised into four groups of five (G1, G2,G3 and G4) and given the following daily treatment for 4 weeks: group one (G1) were administered with 350mg/kg body weight paracetamol via oral gavage and tap water for 24 hours; group 2 (G2) received 350mg/kg paracetamol via oral gavage, 2% (w/v) natural cocoa powder for 12 hours, and water for the next 12 hours ; group 3 (G3) received 350mg/kg paracetamol via oral gavage, 140mg/kg NAC after 3 hours and water for 24 hours; group 4 (G4), served as control group were given 1ml of distilled water via oral gavage and tap water, for 24 hours. All rats were given standard rat chow daily. After week 4, all rats were weighed and sacrificed; livers were harvested and histologically processed for histomorphometric analyses. Relative volume density of hepatocytes and central veins were assessed using standard stereological procedures. Blood samples were collected via tail snipping and milking at the commencement and termination of the experiment. The levels of liver transaminases (AST, ALT), and (SOD, GSH) were measured as indicators of hepatocyte damage and oxidative stress, respectively. Results: After 4 weeks of treatment, the mean serum liver enzymes AST increased significantly (p<0.0001) in G1 (416.37, SD 53.9 IU/L) when compared to G2 (157.12, SD 13.4 IU/L), G3 (170.50, SD 37.1 IU/L) and G4 (154.22, SD 15 IU/L), respectively. The comparison of mean ALT levels in G1 (160.31, SD 15.1IU/L) differed significantly from G2 (108.12, SD 35.3 IU/L) G3 (92.50, SD 19.1 IU/L) and G4 (114.00, SD 3.6 IU/L) respectively. The mean SOD activity was significantly high in G2 (from 0.250, SD 0.15 U/ml to 0.3991, S.D 0.17 U/ml) in comparison with G1 (from 0.256 ± 0.18 U/ml to 0.018, SD 0.01 U/ml). Post treatment mean GSH activity in the serum of rats was significantly decreased in G1 (2.43.1, SD 0.30 uM) when compared to G4 (5.995, SD 0.46 uM). GSH activity after the experiment was significantly increased among rats in G2 (8.676, SD 0.69 uM) and G3 (8.255, SD 1.18 uM) when compared to G4 (5.995, SD 0.46Um). Histomorphometric assessment indicated that G1 rats showed significant increase in the volume of damaged hepatocyte (0.13, SD 0.027) in comparison with G2 (0.017, SD 0.005) and G3 (0.010, SD 0.002) groups. However, among the four groups there was a significant increase (p < 0.0001) in volume of central vein with G1 group mean volume (4.699, SD 1.297). Conclusion: Natural cocoa powder exerts hepatoprotective action and increased antioxidant activity against paracetamol-induced structural and functional liver damage in male Sprague dawley rats.