Anti-inflammatory Steroid from Phragmitis rhizoma Modulates LPS-Mediated Signaling Through Inhibition of NF-κB Pathway

Lipopolysaccharides (LPS) strongly stimulate immune cells, and unabated activation of immune system by LPS may lead to an exacerbation of sickness and depression. In this study, stigmasta-3,5-dien-7-one (ST) was isolated from Phragmitis rhizoma as a negative regulator of LPS-induced inflammation in macrophages. ST effectively reduced nitric oxide (NO), prostaglandin E₂, and pro-inflammatory cytokine levels, which were markedly raised by LPS treatment. In addition, ST blocked the nuclear factor-kappa B (NF-κB) signaling pathway via down-regulation of phospho-p38 mitogen-activated protein kinase and phosphorylation and degradation of the inhibitor of NF-κB α. To our knowledge, this is the first study showing anti-inflammatory activities of ST isolated from Phragmitis rhizoma.