Ph ton 306 International Journal of Pharmacy. Photon 104 (2013) 306-314 https://sites.google.com/site/photonfoundationorganization/international-journal-of-pharmacy Original Research Article. ISJN: 8237-7516 International Journal of Pharmacy Ph ton Hepatoprotective Activity of Three Cameroonian Medicinal Plants against Oxidative Damages induced by Paracetamol- and CCl 4 in Primary Rat Hepatocytes Frederic Nico Njayou a , Borris Rosnay Galani Tietcheu a,b , Bonaventure Tchaleu Ngadjui c , Paul Fewou Moundipa a * a Laboratory of Pharmacology and Toxicology, Department of Biochemistry, Faculty of Science, University of Yaounde 1, Yaounde, Cameroon b Department of Biological Sciences, Faculty of Science, University of Ngaoundere, Ngaoundere, Cameroon. PO Box. 454 Ngaoundere c Laboratory of Natural Substances and Organic Synthesis, Department of Chemistry, Faculty of Science, University of Yaounde 1, Yaounde, Cameroon Article history: Received: 13 September, 2013 Accepted: 16 September, 2013 Available online: 31 October, 2013 Keywords: Hepatocytes, paracetamol, carbon tetrachloride, hepatoprotection, Khaya grandifoliola, Entada africana, Xylopia phloiodora Corresponding Author: Moundipa P.F.* Professor Email: pmoundipa@hotmail.com Phone: +23777310383 Njayou F.N. Email: njayou@yahoo.com Phone: +23775002224 Tietcheu B.R.G. Email: borristietcheu@yahoo.fr Phone: +23775739149 Ngadjui B.T. Email: ngadjuibt@yahoo.fr Abstract Background: Medicinal plants are frequently used in Cameroonian traditional medicine for the treatment of liver-related disorders. Oxidative stress plays an important role in the pathogenesis of these diseases. Objective: The aim of this study was to evaluate in vitro the hepatoprotective effects of K. grandifoliola, E. africana and X. phloiodora against oxidative injuries induced by paracetamol (APAP) or carbon tetrachloride (CCl4) in primary rat hepatocytes. Methods: Freshly isolated rat hepatocytes were pre-incubated with various concentrations of plant extracts or silymarin for 30 min, then APAP or CCl4 was added for 90 min. Then, hepatoprotection was assessed by measuring cell viability, alanine aminotransferase (ALT) leakage into culture medium and the formation of malondialdehyde (MDA). Results Pretreatment of cells with plant extracts or silymarin at concentrations of 0.1, 1, 10, 100 and 1000 μg/ml improved cell viability, reduced ALT leakage and MDA levels. K. grandifoliola and E. africana extracts in particular displayed stronger cytoprotective effects against APAP or CCl4 injury compared to silymarin at same addition level. In addition, K. grandifoliola extract contains the highest amount of polyphenols. Conclusion: K. grandifoliola and E. africana extracts, showed better hepatoprotection on primary hepatocytes against APAP or CCl4- induced damage. Further investigations are needed to identify their active ingredients against hepatotoxicity. Citation: Njayou F.N., Tietcheu B.R.G., Ngadjui B.T., Moundipa P.F., 2013. Hepatoprotective Activity of Three Cameroonian Medicinal Plants against Oxidative Damages induced by Paracetamol- and CCl4 in Primary Rat Hepatocytes. International Journal of Pharmacy. Photon 104, 306-314. 1. Introduction 1.1 Previous studies on medicinal plants investigated Khaya grandifoliola C.D.C (Meliaceae), Entada africana Guill et Perr. (Mimosaceae) and Xylopia phloiodora Mildbr (Annonaceae) have been used in the western, center and southern regions of Cameroon by traditional healers for curing hepatitis and other liver related diseases (Moundipa et al., 2002, 2007). From previous phytochemical studies, seven limonoids and one catechin from the bark and seeds extract of K. grandifoliola have been characterized (Bickii et al., 2000). Polyphenols have been identified in stem bark extracts of K. grandifoliola and E. africana (Njayou et al., 2004) while X. phloiodora was found to contain