Inhibitory effect of citral on NO production by suppression of iNOS expression and NF-κB 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 (IC50: 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.