[摘要]：The present study reports the antiinflammatory activity of a methanol extract isolated from the stem bark of Magnolia kobus (MK). MK potently inhibited lipopolysaccharide (LPS)-induced production of nitric oxide and interieukin-1 beta (IL-1 beta) in RAW 264.7 cells, a murine macrophage-like cell line. The secretion of tumor necrosis factor-alpha (TNF-alpha) was also suppressed in LPS-stimulated RAW 264.7 cells although the magnitude of inhibition was weaker than that of nitric oxide and IL-1fi. The mRNA expressions of inducible nitric oxide synthase (iNOS), IL-1 beta and TNF-alpha were also suppressed by MK in LPS-stimulated RAW 264.7 cells. Further study demonstrated that LPS-induced DNA binding of AP-1 and phosphorylation of e-jun N-terminal kinase (JNK) were inhibited by MK treatment in RAW 264.7 cells, whereas phosphorylation of p38 mitogenactivated protein kinase was unaffected. Moreover, topical application of MK suppressed ear swelling in 12-0-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation model. Collectively, these results suggest that MK exerts antfinflammatory effects in vitro and in vivo and this might be mediated, at least in part, by blocking AP-1 and JNK activation. Copyright (c) 2008 John Wiley & Sons, Ltd.
