## 4 Discussion  
Liver disease is responsible for an estimated two million deaths per year worldwide. In low-income countries, it is the most neglected health issue [16; 17]. The liver is a key organ involved in the regulation of diverse processes including metabolism, detoxification, and immune function, and therefore, it is the frequent target of chemical injury. The liver is the only visceral organ that possesses the ability to regenerate damaged tissue after either surgical removal or after chemical injury. However, multiple cases, such as hepatitis virus, long-term alcohol use, many different drugs, and xenobiotics including carbon tetrachloride may cause chronic liver damage in which regenerative ability becomes dysfunctional [18; 19]. Carbon tetrachloride is widely used as a key substance to investigate liver injury models in animals and dysfunction of hepatic cells which is associated with oxidative stress and free radicals [2]. The mechanisms of carbon tetrachloride-induced liver injury involve the accumulation of lipid peroxidation or covalent binding of carbon tetrachloride metabolites to cell constituents [20; 21]. The present work aimed to evaluate the potential hepatotoxicityective effect of polyphenols extracted from _A. europaea_ against carbon tetrachloride-induced chronic liver injury in mice. The phytochemical study of _A. europaea_ using high-performance liquid chromatography revealed the presence of interesting chemicals including fertile acid, gallic acid, methyl gallate, rutin, and resorcinol (Figures 3 and 4; Table 1). Our results were partially in agreement with previous works reporting some similar compounds [4; 8]. The biochemical parameters AST and ALT are frequently used to indicate liver function after being exposed to chronic injuries. Liver damage stimulates the release of amino-transferases from damaged hepatocytes, which become higher in the blood circulatory system [22]. The treatment of mice with _A. europaea_ polyphenols at a dose of 50 mg/Kg showed no histological nor biochemical alterations, and therefore, we can confirm its safety in animals (Figures 5 and 6; Table 2). In the plasma of mice treated with carbon tetrachloride alone (group 3), AST (U/L) and ALT (U/L) significantly increased when compared to the untreated group (Table 2). The serum activity of transaminases was also not significantly affected in the plasma recovered from the experimental group 4 (poly A.E + CCI4) when compared to both group 3 (CCl4 alone) and group 1 (NaCl). Based on the results obtained, it is evident that the oral administration of _A. europaea_ polyphenols at a dose of 50 mg/Kg maintained the activity of transaminases around a normal level in the mice treated with carbon tetrachloride during the whole period of dosing. These data were also supported by histopathological analysis of liver recovered from the mice treated with carbon tetrachloride alone, where we noted serious histopathological modifications, unlike group 1 (NaCl) and group 3 (poly A.E + CCI4) (Figures 5 and 6). These results were in agreement with those reported in the earlier literature, which showed that carbon tetrachloride induces severe histological liver injury [20]. The histopathological analysis of liver sections excised from group 2 treated with carbon tetrachloride alone showed the presence of various serious histopathological alterations including cavitations and necrosis as well as nuclear changes. These results are consistent with those found by [PERSON] et al. (2011) in rats treated with carbon tetrachloride [14]. No significant histological modifications were noted for liver sections recovered from the mice treated with poly A.E+ CCI4 (group 3) when compared to group 2 (CCl4 alone). These data suggest that polyphenols of _A. europaea_ may have an interesting role in protecting the liver from xenobiotics including carbon tetrachloride, and therefore, we can confirm that polyphenol-rich fractions from _A. europaea_ protected the liver from being altered by carbon tetrachloride.