Anti-inflammatory activity of Schizonepeta tenuifolia through the inhibition of MAPK phosphorylation in mouse peritoneal macrophages.

Schizonepeta tenuifolia (ST) is a well-known herb to treat the cold and its associated headache. However, the anti-inflammatory mechanism of ST in mouse peritoneal macrophages is not clear. In this study, we demonstrated that ST inhibited lipopolysaccaride (LPS)-induced tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 production. The maximal inhibition rate of TNF-alpha and IL-6 production by ST (2 mg/ml) was 48.01 +/- 2.8% and 56.45 +/- 2.8%, respectively. During the inflammatory process, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) were increased in mouse peritoneal macrophages. However, treated with ST decreased the protein level of COX-2 and iNOS, as well as the production of PGE(2) and NO in LPS-stimulated mouse peritoneal macrophages. In addition, ST inhibited the phosphorylation of MAPK. Taken together, the results of this study suggest an important molecular mechanism by which ST reduces inflammation, which may explain its beneficial effect in the regulation of inflammatory reactions.