Thiazolidinedione Derivative Suppresses LPS-induced COX-2 Expression and NO Production in RAW 264.7 Macrophages

The present study was designed to investigate the inhibitory effect of 2,4 bis-[(4- ethoxyphenyl)azo] 5-(3-hydroxybenzylidene) thiazolidine-2,4-dione (TZD-OCH2CH3) on the cyclo-oxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in RAW 264.7 cells. The effects of TZD-OCH2CH3 on COX-2 and iNOS mRNA expression in LPS-activated RAW 264.7 cells were detected by real time PCR. Also, to understand structure and substrate specificity, we have utilized molecular docking simulations (AutoDock Vina) and the active residues in the binding pocket were determined from COX-2 and iNOS. The treatment of RAW 264.7 cells with TZD-OCH2CH3 significantly inhibited LPS-induced COX-2 mRNA expression, corresponding to 46.1% and 61.06% at 30 and 60 μg/mL, respectively. The present study revealed that the TZD-OCH2CH3 had a little effect on iNOS mRNA expression. Meanwhile, the TZD-OCH2CH3 also could inhibit the production of NO compared to single LPS-stimulated cell. According to the results obtained, TZD-OCH2CH3 dramatically suppressed lipopolysaccharide (LPS) induced nitric oxide (NO) production after 24 h, in a concentrationdependent manner with an IC50 of 65 μg/mL. Our data suggest that TZD-OCH2CH3, as a functionally novel agent, inhibits the inflammatory pathway via suppression of COX-2 mRNA expression and also by the inhibition of the iNOS activity. Therefore, this compound could be suggested as a novel therapeutic strategy for inflammation-associated disorders.