EBSHealth Doğu Karadeniz Sağlık Bilimleri Dergisi, East Black Sea Journal of Health Sciences Cilt 1, Sayı 3, 2022 Effects of Alpha-Lipoic Acid on Polyphenol Oxidase Activity in Small Intestine Tissue of Rats Treated with Acitretin - Methotrexate Combination Fatma Gönül SEZGİN 1 , Emine İncilay TORUNOĞLU 2 , Emine DIRAMAN 3 * Research Article/AraştırmaMakalesi Geliş Tarihi / Received: 19.12.2022 Kabul Tarihi / Accepted: 29.12.2022 ABSTRACT Background and Aim: Acitretin is a vitamin A analogue, which is a lipophilic weak acid, less soluble in water and less accumulated in adipose tissue. It is also non-immunosuppressive with anti-inflammatory and anti-proliferative effects. Methotrexate, an inhibitor of thymidylate synthetase and dihydrofolate reductase, is a folic acid analogue. Today, Methotrexate, which is used in the treatment of diseases such as mycosis fungoides, pityriasis rubra pilaris, dermatomyositis, sarcoidosis, eczema, as well as cancer treatments, is also an anti-folate antimetabolite agent. It has also been used together with Acitretin in treatment. In this study, Alpha Lipoic Acid, which is a powerful antioxidant, was given to rats to eliminate the damage caused by free radicals that may occur as a result of Acitretin-Methotrexate application. Thus, it is aimed to investigate the effect of Alpha Lipoic Acid, which plays an important role in repairing the oxidative damage that may occur, on the polyphenol oxidase (1.10.3.1) enzyme activity in the small intestine tissue. Polyphenol oxidase, containing copper in its active site, is an oxidoreductase class enzyme that catalyzes the oxidation of phenolic compounds with molecular oxygen. Materials and Methods: Four study groups were formed as Control Group, Alpha Lipoic Acid Group, Acitretin+Methotrexate Group and Acitretin+Methotrexate+Alpha Lipoic Acid Group. The injection procedures applied to the rats were performed at the same time every morning and they were fasted 24 hours before the injection. Acitretin, Methotrexate and Alpha lipoic acid were dissolved in 0.9% NaCl and given to rats by intraperitoneal injection. Rats were sacrificed by cervical dislocation on the 7th day after injection. Following this, cardiac perfusion was performed and the small intestines were removed. The samples were first homogenized, then sonication and centrifugation processes were applied. After centrifugation, the obtained small intestine homogenates were used for Polyphenol oxidase activity determination. Result and Conclusion: Alpha Lipoic Acid, Acitretin + Methotrexate and Acitretin + Methotrexate + Alpha Lipoic Acid groups were compared with the control group. As a result, while it was observed that the Alpha Lipoic Acid group had almost the same activity with the Control group (1.65% activation), the Acitretin + Methotrexate group showed 10% activation, the Acitretin + Methotrexate + Alpha Lipoic Acid group showed 25% activation. When the Acitretin + Methotrexate group was compared with the Acitretin + Methotrexate + Alpha Lipoic Acid group, it was also determined that the Acitretin + Methotrexate + Alpha Lipoic Acid group showed 13.5% more activation. While Alpha Lipoic Acid did not show a significant difference in Polyphenol oxidase activity in small intestine tissue when given alone, it increased Polyphenol oxidase activity when given with Acitretin + Methotrexate combination. Keywords: Small intestine, acitretin, methotrexate, polyphenol oxidase 1 PhD, Res. Asst. Ondokuz Mayıs University, Faculty of Science, Department of Molecular Biology, Samsun/Turkey, email: gonul.solmaz@omu.edu.tr, ORCID ID: 0000-0002-9400-5173 2 PhD student, Necmettin Erbakan University, Faculty of Medicine, Department of Biochemistry, Samsun/Turkey, email: torunogluemineincilay@gmail.com, ORCID ID: 0000-0003-4641-0067 3 Assoc. Prof. Dr., Ondokuz Mayıs University, Faculty of Science, Department of Molecular Biology, Samsun/Turkey, email: ediraman@omu.edu.tr, ORCID ID: 0000-00002-4677-1738 *Corresponding author