en سم شناسی Toxicology پژوهشي Original Research In the present study, we aimed to examine the potential protective effect of <em>C. aurantinum L.</em> peel extract against oxidative damage induced by hexavalent chromium in the heart of adult rats. Rats were divided into six groups. Group I served as controls and received standard diet. Group II received via drinking water potassium dichromate (K₂Cr₂O₇) alone (700 ppm) during 3 weeks. Groups III and IV were pre-treated for 10 days by gavage with the ethanolic extract of <em>C. aurantium </em>peels at doses of 100 and 300 mg/kg body weight/day, respectively, and then K₂Cr₂O₇ was administrated during 3 weeks. Groups V and VI received by gavage only <em>C. aurantium </em>peel ethanolic extract at doses of 100 and 300 mg/kg body weight/day, respectively, during 10 days. K₂Cr₂O₇ treatment increased the cardiac levels of malondialdehyde (MDA), protein carbonyls (PCO), advanced oxidation protein products (AOPP), non-protein thiols, glutathione and vitamin C, as well as the activities of catalase, superoxide dismutase and glutathione peroxidase. Cardiac histological alterations, manifested by hemorrhage and cytoplasmic vacuolization, were also observed. Pre-treatment with <em>C. aurantium </em>peel extract (300 mg/kg) attenuated significantly the biochemical and histopathological changes observed following K₂Cr₂O₇exposure in rat&rsquo;s heart. Our findings indicated that <em>C. aurantium </em>peel extract was able to hamper K₂Cr₂O₇-induced myocardial injury, which could be attributed to its antioxidant activity. Chromium, rats, heart, oxidative stress, c. aurantium peel 8 18 http://pbr.mazums.ac.ir/browse.php?a_code=A-10-206-1&slc_lang=en&sid=1 Mariem Chaabane maryame.ch@yahoo.com 10031947532846003789 10031947532846003789 Yes Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University of Sfax, BP 1171, 3000 Sfax, T unisia Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University Awatef Elwej awatefelwej@yahoo.fr 10031947532846003790 10031947532846003790 No Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University of Sfax, BP 1171, 3000 Sfax, T unisia Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University of Sfax, BP 1171, 3000 Sfax, Tunisia Imen Ghorbel ghorbel21@gmail.com 10031947532846003791 10031947532846003791 No Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University of Sfax, BP 1171, 3000 Sfax, T unisia Department of Life Sciences, Sciences Faculty of Sfax, University of Sfax, BP 1171, 3000 Sfax, Tunisia Tahia Boudawara tahya.Sellami@fmsf.rnu.tn 10031947532846003792 10031947532846003792 No Hist opathology Laboratory, University of Sfax, CHU Habib Bourguiba, 3029 Sfax, Tunisia Histopathology Laboratory, University of Sfax, Najiba Zeghal naj_zgh@yahoo.fr 10031947532846003793 10031947532846003793 No Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University of Sfax, BP 1171, 3000 Sfax, T unisia Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University Nejla Soudani nejla.soudani@tunet.tn 10031947532846003794 10031947532846003794 No Unit of P hysiology and Aquat ic Environment, T unis Facult y of Science, University of T unis El Manar, 2092, T unis, Tunisia Animal Physiology Laboratory, Department of Life Sciences, Sciences Faculty of Sfax, University