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Antiinflammatory activity of methanol extract isolated from stem bark of Magnolia kobus

Kang, Jong Soon, Lee, Ki Hoon, Han, Mi Hwa, Lee, Hyunju, Ahn, Ji‐Mi, Han, Sang‐Bae, Han, Gyoonhee, Lee, Kiho, Park, Song‐Kyu, Kim, Hwan Mook
Phytotherapy research 2008 v.22 no.7 pp. 883-888
DNA, Magnolia kobus, anti-inflammatory activity, bark, ears, gene expression, inflammation, lipopolysaccharides, messenger RNA, mice, mitogen-activated protein kinase, models, necrosis, nitric oxide, nitric oxide synthase, phosphorylation, secretion, topical application
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 interleukin‐1β (IL‐1β) in RAW 264.7 cells, a murine macrophage‐like cell line. The secretion of tumor necrosis factor‐α (TNF‐α) was also suppressed in LPS‐stimulated RAW 264.7 cells although the magnitude of inhibition was weaker than that of nitric oxide and IL‐1β. The mRNA expressions of inducible nitric oxide synthase (iNOS), IL‐1β and TNF‐α 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 c‐jun N‐terminal kinase (JNK) were inhibited by MK treatment in RAW 264.7 cells, whereas phosphorylation of p38 mitogen‐activated protein kinase was unaffected. Moreover, topical application of MK suppressed ear swelling in 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)‐induced skin inflammation model. Collectively, these results suggest that MK exerts antiinflammatory effects in vitro and in vivo and this might be mediated, at least in part, by blocking AP‐1 and JNK activation. Copyright © 2008 John Wiley & Sons, Ltd.