en Dentistry Dentistry Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><strong><em><span style="color:#0000ff;">Background:</span></em> </strong>Nowadays, radiotherapy is used effectively for treatment of head and neck cancers. Mucositis is one of the most important side effects of radiotherapy. Radio-protective agents protect tissues and cells against the adverse effects due to ionizing radiation and cleave radiation-induced free radicals. Lycopene as a potent antioxidant protects cells against oxidative damage by free radical&ndash;scavenging. &nbsp;The present study investigated the antioxidant effect of lycopene on oral mucosa of irradiated rats.<span dir="RTL"></span><br> <strong><em><span style="color:#0000ff;">Methods:</span></em> </strong>In this experimental animal study, 28 rats were placed in four groups as follows: treated with 50 mg /kg of lycopene (L50), solvent+irradiation (SR), 25 mg / kg of lycopene+irradiation (LR25), and 50 mg / kg of lycopene+irradiation (LR50). The rats received lycopene intraperitoneally. On the irradiation day (day 0) and tenth day of radiation, blood samples were taken from the animals for FRAP and TBARS tests.<strong><span dir="RTL"></span></strong><br> <strong><em><span style="color:#0000ff;">Results:</span></em> </strong>The results showed that the LR50 group didn&rsquo;t show mucositis higher than Grade 2. There was a significant difference (p <0.05) between SR and the L50 regarding the severity of mucositis. In addition, L50 showed higher antioxidant activity and lower peroxidation than SR. <span dir="RTL"></span><br> <strong><em><span style="color:#0000ff;">Conclusion:</span></em> </strong>The lycopene reduced the severity of mucositis. Therefore, it can be used as a potential and promising nutritional substance to prevent radiotherapy complications, especially in the treatment of head and neck cancers. However, further research is necessary to confirm these results.<span dir="RTL"></span><br> &nbsp;</span></span> Antioxidant activity, Irradiation, Lycopene, Mucositis, Radiotherapy 419 425 http://caspjim.com/browse.php?a_code=A-10-1665-1&slc_lang=en&sid=1 Mina Motallebnejad mmotallebnejad@yahoo.com 100319475328460024939 100319475328460024939 No Oral Health Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Shaghayegh Zahedpasha shaqayeq.zahedpasha@gmail.com 100319475328460024940 100319475328460024940 No Department of Oral Medicine, Faculty of Dentistry, Mazandaran University of Medical Science, Sari, Iran Ali Akbar Moghadamnia moghadamnia@gmail.com 100319475328460024941 100319475328460024941 No Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Sohrab Kazemi kazemi.msm@gmail.com 100319475328460024942 100319475328460024942 No Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Daryoush Moslemi d_moslemi@yahoo.com 100319475328460024943 100319475328460024943 No Cancer Research Center, Health Research Institute. Babol University of Medical Sciences, Babol, Iran. Mahdi Pouramir pouramir@yahoo.com 100319475328460024944 100319475328460024944 No Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran Fariba Asgharpour f_asgharpour@yahoo.com 100319475328460024945 100319475328460024945 Yes Dental Materials Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran