Some Protective Effects of Aqueous Leaf Extract of Azadirachta indica on Paracetamol-induced Hepatotoxicity in Adult Wistar Rats

Abstract

Background: Azadirachta indica is a plant used widely in the Indian system of medicine for its diverse medicinal properties. Its extracts have a vast pharmacological activity and are used as raw materials for pesticide, medicine and other commodities. Each part of this plant have its own therapeutic importance and uses which include: antifertility antipyretic, anti-inflamatory, antimalaria, anti-rheumatic and others. The present study investigated some effects of aqueous extract of Azadirachta indica on paracetamol-induced hepatotoxicity in adult wistar rats. Place and Duration of Study: Department of Anatomy, Faculty of Basic Medical Sciences, LAUTECH, Nigeria between November 2009 and July 2010.  Methodology: A total of twenty-four (24) rats of wistar strain of both sexes weighing 150g-232g were divided into four (4) groups of six (6) rats each. Groups A served as normal control given only distilled water for seven days orally. Group B received only paracetamol at a dose of 3g/kg body weight orally, on the fifth day of seven days administration, group C received a pretreatment of Azadirachta indica aqueous extract at a dose (400mg/kg b.w orally) for seven days while paracetamol (3g/kg .orally) was given on the fifth day of the administration and group D only received the aqueous extract of Azadirachta indica (400mg/kg/ b.w.) orally 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 of hepatic marker enzymes Alanine amino transaminase (ALT), Aspartate amino transaminase (AST) and Alkaline phosphatase (ALP) 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 obtained from body weight parameter showed that paracetamol treated group (group B) showed a significant reduction in weight compared to groups A, C and D. Histopathological observations revealed well preserved histoarchitecture, without portal inflammation, cytoplasmic inclusion, binucleation or necrosis in group A, C and D. However, group B showed portal inflammation, moderate to mild cytoplasmic inclusion, sinusoid congestion and marked tissue necrosis in most of the group compared with group C in which the leaf extract of Azadirachta indica inhibited paracetamol induced hepatic damage. Biochemical analysis of hepatic enzymes also showed an increased in serum marker enzymes of hepatic damage (AST, ALT and ALP) after paracetamol administration in group B. Azadirachta indica pretreatment stabilized the serum levels of these enzymes in group C and D, respectively. Conclusion: The study concluded that aqueous leaf extract of Azadirachta indica offers protection to the hepatocytes against paracetamol induced hepatotoxicity in wistar rats.