Ginsenoside Rh2 attenuates allergic airway inflammation by modulating nuclear factor-κB activation in a murine model of asthma.

Allergic asthma is a chronic inflammatory disease that is regulated by coordination of T-helper type 2 cell cytokines and inflammatory signaling molecules. Ginsenoside Rh2 (G-Rh2) is an active component of ginseng with anti-inflammatory and anti-tumor effects. The aim of the present study was to determine the inhibitory effects of G-Rh2 on allergic airway inflammation in a murine model of asthma, in which mice develop the following pathophysiological features of asthma: Increased abundance of inflammatory cells; increased levels of interleukin-4 (IL-4), IL-5 and IL-13; decreased abundance of interferon gamma in the bronchoalveolar lavage fluid and lung tissue; increased total and ovalbumin (OVA)-specific immunoglobulin E (IgE) levels in the serum; increased airway hyperresponsiveness (AHR); and activation of nuclear factor kappa B (NF-κB) in lung tissue. In the asthmatic mice, administration of G-Rh2 markedly reduced peribronchiolar inflammation, recruitment of airway inflammatory cells, cytokine production, total and OVA-specific IgE levels and AHR. G-Rh2 administration inhibited NF-κB activation and p38 mitogen-activated protein kinase (MAPK) phosphorylation induced by OVA inhalation. These results suggested that G-Rh2 attenuates allergic airway inflammation by regulating NF-κB activation and p38 MAPK phosphorylation. The present study identified the molecular mechanisms of action of G-Rh2, which supported the potential use of G-Rh2 to prevent and/or treat asthma and other airway inflammatory disorders.