IRINA C. CHIS, DOINA BALTARU, SIMONA CLICHICI, OVIDIU ONIGA, ILEANA COJOCARU, CRISTINA NASTASA THE EFFECTS OF A 5-CHROMENE-YL-THIAZOLIDIN-2,4-DIONE DERIVATIVE IN ALLEVIATING OXIDATIVE STRESS IN ADJUVANT-INDUCED ARTHRITIS Rheumatoid arthritis (RA) is a chronic inflammatory disease that reduces life quality and requires long-life therapy. Quercetin (Que) is a natural flavonoid with antioxidant and anti-inflammatory effects. (3-(2-(4-Chlorophenyl)-2-oxoethyl)-5-((6-methyl-4-oxo-4H-chromen-3-yl)methylene) thiazolidine-2,4-dione (TZD) is a thiazolidinedione derivative synthesized in our laboratory. This study was designed to investigate the antioxidant effects of the Que and TZD derivative administration in adjuvant-induced arthritic (AIA) rats. AIA was induced in Wistar rats by the intraplantar injection of Freund’s complete adjuvant (FCA), unilaterally in the right hind paw. The control non-arthritic rats and the arthritic rats were treated with Que (30 mg/kg/day) or TZD derivative (12 mg/kg/day) for 21 days. The antioxidant effects of 5-chromen-yl- thiazolidinedione were compared to Que. The serum levels of malondialdehyde (MDA) and protein carbonyl (PC) groups, the superoxide dismutase (SOD) and catalase (CAT) activity were assessed. AIA rats showed significatly increased oxidative stress parameter levels in the blood. The results indicated that the TZD derivative decreased the blood oxidative stress parameters in the treated arthritic rats, compared to Que. The antioxidant effects of 5-chromen-yl-thiazolidinedione in AIA suggest its therapeutic properties for the clinical treatment of RA.