Inhibition by Moxa smoke of NO production and iNOS expression in mouse macrophage-like cells Raw 264.7.

The biological activities of Moxa, used as moxibustion, have not been well documented. We investigated the effect of Moxa smoke on nitric oxide (NO) production by mouse macrophage-like Raw 264.7 cells. Moxa smoke failed to stimulate the Raw 264.7 cells to produce detectable amounts of NO, but rather inhibited the NO production by lipopolysaccharide (LPS)-activated Raw 264.7 cells. The 50% inhibitory concentration (IC50) of NO production by Moxa smoke (0.16%) was one order lower than the 50% cytotoxic concentration (CC50) (4.67%). Western blot and RT-PCR analyses demonstrated that a slightly higher concentration of Moxa is required to reduce the iNOS expression at protein and mRNA levels (IC50 = 0.99 and 2.03%, respectively). The inhibition of NO production by Moxa smoke is, thus, probably due to both the inhibition of iNOS expression and radical-scavenging activity. The present data suggest the possible anti-inflammatory effect of Moxa smoke.