Protective Effect of Methanol Stem Bark Extract of Cocos nucifera on Paracetamol-induced Hepatotoxicity in Adult Wistar Rats

Abstract

Background: Cocos nucifera is a plant used widely in the African system of medicine for its diverse medicinal and nutritional properties. Its extracts have a vast pharmacological activity and are used as raw materials for medicine and other commodities. Each part of this plant has its own therapeutic importance and uses which include: anticancer, reproductive, anti-inflammatory, anti-malaria, antioxidant and others. The present study investigated the effect of methanolic extract of Cocos nucifera stem back on liver marker enzymes and liver histology of paracetamol exposed hepatotoxic rats using standad protocols. Methodology: A total of twenty (20) male wistar rats distributed normally into five groups (n=4) were used for the study. Group I rats served as normal control and were not exposed to paracetamol, while groups II, III, IV and V rats were exposed to 750 mg/kg body weight of paracetamol served as intoxicated test groups. Groups II, III, IV and V were treated with 0.5 ml distilled water, 25 mg/kg body weight of silymarin, 200 mg/kg and 400 mg/kg body weight of C. nucifera stem bark extract respectively for seven days. At the end of the experimental period, all animals were sacrificed using cervical dislocation method; blood was obtained for assay for the following hepatic marker enzymes Alanine amino transaminase (ALT), Aspartate amino transaminase (AST), Alkaline phosphatase (ALP) and total bilirubin respectively. Liver tissue was removed, fixed in 10% formol saline and processed for histopathological studies using Heamatoxylin and Eosin (H and E) staining technique. Results: The results indicated the presence of the phytochemical content of the extract in the order: tannins > soluble carbohydrates > flavonoids > alkaloids > saponnins > steroids. Result of the acute toxicity test showed that the extract is safe at a dosage of up to 5000 mg/kg body weight. The results showed that induction of paracetamol caused significant (P<0.05) increase in the marker enzymes and a multiple, mild to moderate periportal infiltration of mononuclear leucocytes in hepatocytes. It was observed that treatment with the extract caused dose-dependent significant (P<0.05) decrease in plasma aspartate amino transaminase (AST), alanine amino transaminase (ALT), Alkaline phosphatase (ALP) and bilirubin concentrations and increased protection in the damaged hepatocytes. Conclusion: The hepato-protective activities of this extract might be attributed to the bioactive compounds present and as such implicates the extract as potent tool for ethnomedical practice.