In vivo Hepatoprotective Effect of Combretum micranthum Leave Extract

Abstract

Introduction The liver is one of the important organs in the body. Owing to its vital function, it is often exposed to numerous exogenous injurious substances that may result in different hepatic diseases. A number of medicinal plants are used to cure hepatic disorders in traditional herbal medicine. The leaves of Combretum micranthum (CM) belonging to the family Combretaceae are used traditionally in the treatment of fever and ailments of liver and gall bladder. The aim of this study is to investigate the hepatoprotective effect of its aqueous leaf extract in female Sprague-Dawley rats. Method The leaves of CM were air dried to constant weight and extracted with distilled water using a soxhlet apparatus. The extract was dried at 60 0C in an oven and stored in a refrigerator. In a pre-treatment model study, rats were divided into six groups of 6 animals each. Group I (normal control) received distilled water (10 ml/kg) daily, Group II (paracetamol/toxic control) also received distilled water (10 ml/kg) daily, Group III served as the standard control and received silymarin (100 mg/kg) daily, Group IV-VI served as the treatment groups and received 125, 250 and 500 mg/kg of CM daily. All treatments were given orally for seven days. On the seventh day, Groups II-VI received 2 g/kg paracetamol (PCM), 30 min post dosing. 24 h after PCM administration, all the rats were anaesthetized, blood samples collected and serum separated for biochemical analysis. Liver tissues were collected for histological analysis. In a post treatment model, the rats were divided into six groups of 6 animals each. Group A (normal control) were treated with distilled water. Animals in groups B-F received a single dose of PCM (2 g/kg) on day 1. Group B served as the paracetamol/toxic control. Groups C-F received 125, 250 and 500 mg/kg of CM and silymarin (100 mg/kg) respectively 2, 24 and 48 h after PCM administration. All the animals were sacrificed 72 h after PCM administration. Blood samples and liver tissues were collected and handled as described in the pre-treatment model. Data are presented as mean ± standard error of mean (SEM) and analysed by One-way analysis of variance (ANOVA) and Tukey post-test using SPSS (version 21.0). p<0.05 were considered significant. Results In the pre-treatment model, the paracetamol/toxic group showed an increase in the mean values of the liver marker enzymes namely: alkaline phosphate (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and total protein (TP). CM at 125, 250 and 500 mg/kg and silymarin caused a dose dependent reduction in three of the markers, namely: ALP, AST and TP compared to the paracetamol/toxic control. This is presented in Table 1. In the post treatment model, the paracetamol/toxic group showed similar increase in the mean values of the measured marker enzymes. Aqueous extract of CM reduced two of these markers, namely: AST and TP in a non-dose dependent manner as shown in Table 2. The histological results further confirmed the results of the biochemical analysis Conclusion The aqueous extract of CM possess some hepatoprotective property against paracetamol induced hepatotoxicity, with a better activity as preventive (pre-treatment) rather than curative (post-treatment). This may provide a possible explanation for its traditional use in the treatment of liver diseases.