Inducible nitric oxidase synthase iNOS

In the production of injurious substances, i.e., oxidants, EM was proved to inhibit HADPH/NADH oxidase induction, resulting in the reduction of superoxide anion synthesis [26]. Sato etal. reported that EM exhibited an antioxidant effect in the influenza virus-infected mice model. Although mice infected with influenza virus usually die, EM dramatically improved the survival ratio of infected mice. This improvement is due to the antioxidant effect, which showed inhibition of IFN-y causing attenuation of inducible nitric oxide synthase (iNOS) transcription by erythromycin [95] (Fig. 18). 

EGCG and theaflavins were found to inhibit xanthine oxidase (12,14) and suppress the production of ROS in HL-60 cells (12). EGCG and theaflavins inhibit nitric oxide production, which appears to be mediated through suppression of inducible nitric oxide synthase (iNOS), as demonstrated by its mRNA and protein levels (15,16). Electrophoretic mobility shift assay revealed that theaflavins and EGCG blunted activation of NFkB responsible for iNOS induction (15). These results indicate that these tea polyphenols inhibit the binding of NF /c B to iNOS promoter, thereby suppressing the transcription of iNOS gene. 

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