PP-64 Some Lichen Acids May Be L'sed As A Potcntial Drııg For Cancer Therapy; By Inhibiting Mitochondrial Thioredoxin Reductase ilknur Ozsencli, Harun Budak , Mehmet Ciftci, Mustafa Anar Atatürk University, Faculty of Science, Department ofChemistry, Erzurum 'Atatürk University, Faculty of Science, Department of Molecular Biology and Genetics, Erzurum Bingöl University, Faculty of Science and Art, Department ofChemistry, Bingöl *Corresponding author. E-mail: nur_turk kimyafehotmail.com Abstract Thioredoxin reductase (E.C 1.6.4.5.; TrxR), is a widely distributed flavoprotein, catalyzes the NADPHdependent reduction of thioredoxin (Trx) in many celluiar events including DNA synthesis, redox signaling, antioxidative defence, selenium metabolism, and the regulatmg of apoptosis. Although TrxR protects healthy cells from oxidative stress, the overexpression of TrxR also promotes to tumor growth and progression in the celi. Thus, the inhibition of TrxR has been targeted for chemotherapy approaches [1,2]. in this study, it was the fırst time the enzyme was purifıed from rat lung in two steps as the preparation of homogenate and 2',5'-ADP Sepharose 4B affınity chromatography. After the purification procedure, in vitro inhibition effect of some lichen acids [3] including diffractaic acid, evernic acid, lobaric acid, lecanoric acid, and vulpinic acid on mitochondrial TrxR vvas investigated. Ali of the lichen acids exhibited strong inhibitory effect on the enzyme same as the anticancer agents. Key words: Thiorcdoxin Reductase, Cancer, Lichen Acids References: [1] Vv'ang Y. Zhang 11, llolmgrcn A, Tian W, Zhong 1.. 2008. Oncol. Rcp. 20:1479-1487. [2] Fan. C. Zheng, W.. Fu, X., l.i, X., Vv'ong. Y-S., Chen, T. 2014. Celi Death Dis. April; 5(4): el 191. [3] Rankovic, B., Kosanic, M., Manojlovic, N., Rancic, A., Stanojkovic, T. 2014. Chemical composition of Hypogymnia physodes lichen and biological activities of some its majör metabolites Med Chem Res, 23:408-416. 109