NOS2 and asthma: Glycyrrhizin not only decreases levels of pro-inflammatory cytokines such as interleukin (IL)-1β and TNF-α, but also suppresses the expression of cyclooxygenase-2 (COX-2) and iNOS, reducing the severity of LPS-induced ALI in mice (Ni et al., 2011), and improves long-term histopathologic changes in a murine model of asthma (Hocaoglu et al., 2011).