Moreover, quercetin also prevented the progression of emphysema in an elastase/LPS mouse model by reducing oxidative stress (iNOS and MDA), lung inflammation (keratinocyte-derived protein chemokine (murine IL-8), MCP1, macrophage inflammatory protein 2, IL-1β), and the expression as well as activity of MMP9 and -12. The gene discussed is NOS2; the disease is pulmonary emphysema.