Inhibitory Effect of Citral on NO Production by Suppression of iNOS Expression and $NF-{\kappa}B$ Activation in RAW264.7 Cells

Citral is a major compound of lemongrass (Cymbopogon citratus L.) that has many pharmacological activities such as anti-fungal and anti-bacterial effects. In this study, we investigated the anti-inflammatory effect of citral and defined its mechanism of action in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Citral (3-12 ${\mu}g/mL$) significantly inhibited LPS-induced nitric oxide (NO) production in a concentration-dependent manner ($IC_{50}:\;6.5\;{\mu}g/mL$). Furthermore, it was found that citral effectively inhibited the transcriptional activity and expression of iNOS, and potently suppressed the DNA binding activity and nuclear translocation of $NF-{\kappa}B$ as well as $I{\kappa}B$ phosphorylation in a concentration dependent manner. These results suggest that citral is anti-inflammatory, and its effects may be due to the inhibition of NO production through the suppression of $NF-{\kappa}B$ activation.