Chamomile: An anti-inflammatory agent inhibits inducible nitric oxide synthase expression by blocking RelA/p65 activity

Chamomile has long been used in traditional medicine for the treatment of inflammation-related disorders. In this study we investigated the inhibitory effects of chamomile on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression, and explored its potential anti-inflammatory mechanisms using RAW 264.7 macrophages. Chamomile treatment inhibited LPS-induced NO production and significantly blocked IL-1ß, IL-6 and TNF·-induced NO levels in RAW 264.7 macrophages. Chamomile caused reduction in LPS-induced iNOS mRNA and protein expression. In RAW 264.7 macrophages, LPSinduced DNA binding activity of RelA/p65 was significantly inhibited by chamomile, an effect that was mediated through the inhibition of IKKß, the upstream kinase regulating NF-κB/ Rel activity, and degradation of inhibitory factor-κB. These results demonstrate that chamomile inhibits NO production and iNOS gene expression by inhibiting RelA/p65 activation and supports the utilization of chamomile as an effective antiinflammatory agent.