3.3. Cinnamomum camphora suppresses NO productionstimulated by LPS
Since NO is also known to be a pro-inflammatory mediator in many different acute and chronic inflammatory diseases (Payne, 2003), we next addressed whether Cinnamomum camphora modulates NO production from the macrophages activated by LPS and/or IFN-␥. According to nitrite assay, the hexane and EtOAc extracts (100g/ml) from Cinnamomum camphora strongly inhibited NO production in the LPS/IFN-␥-activated macrophages up to76 and78%, respectively. Analyses of the iNOS expression using both RT-PCR (Fig. 2, left panel)and Western blotting (Fig. 2, right panel), however, showed that EtOAc fraction (100g/ml) suppressed both mRNA and protein levels of iNOS up to 50–80%. The standard compound , N-MMA, showed a significant inhibitory effect on NO production, with IC50 values of 191.4 (upon LPS signal) and 128.7 M(IFN-␥), respectively.