Suppression of tumour necrosis factor-alpha by Schizonepeta tenuifolia water extract via inhibition of IkappaBalpha degradation and Jun N-terminal kinase/stress-activated protein kinase activation.
OBJECTIVE
The anti-inflammatory effects of an aqueous extract of Schizonepeta tenuifolia on lipopolysaccharide (LPS)-induced tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in vivo and in vitro have been investigated.


METHODS
C57BL/6 mice were orally administered phosphate-buffered saline (control) or S. tenuifolia water extract (50, 200, 500 or 1000 mg/kg) for 10 days before intraperitoneal administration of LPS (1.3 mg/kg). Blood samples were obtained 1 h after LPS challenge, followed by determination of TNF-alpha and IL-6 levels. Peritoneal macrophages from thioglycollate-injected mice were obtained and stimulated with LPS and S. tenuifolia water extract for viability assay, cytokine analysis, real-time RT PCR and Western blotting.


RESULTS
Oral administration of S. tenuifolia water extract to mice significantly reduced LPS-induced serum levels of TNF-alpha, but not IL-6. When peritoneal macrophages were treated in vitro with S. tenuifolia water extract, the inhibition of LPS-induced TNF-alpha was more pronounced than that of IL-6 at the level of secreted protein and mRNA. S. tenuifolia water extract reduced the degradation of IkappaBalpha and the nuclear relocation of p65 NF-kappaB, but the phosphorylation of IkappaBalpha was not affected. Inhibition of c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) by S. tenuifolia water extract led secondarily to the inhibition of phospho-c-Jun and phospho-ATF-2.


CONCLUSIONS
These results indicated that the downregulation of TNF-alpha by S. tenuifolia water extract may have involved the inhibition of both IkappaBalpha degradation and activation of c-Jun and ATF-2 involving suppression of JNK/SAPK.
Kang
Hee
H
Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Yongin-si, Gyeonggi-do, South Korea. shehee@khu.ac.kr
Han
Sang-Woo
SW
Hong
Joung-Woo
JW
Sohn
Nak-Won
NW
D051698:Activating Transcription Factor 2 / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D000284:Administration, Oral; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015153:Blotting, Western; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004789:Enzyme Activation; D020672:I-kappa B Proteins / Q000378:metabolism*; D007249:Inflammation / Q000139:chemically induced / Q000201:enzymology / Q000276:immunology / Q000517:prevention & control*; D015850:Interleukin-6 / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D019686:Lamiaceae; D008070:Lipopolysaccharides; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D000072000:NF-KappaB Inhibitor alpha; D010766:Phosphorylation; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D011499:Protein Processing, Post-Translational; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000235:genetics / Q000378:metabolism*
D051698:Activating Transcription Factor 2; D000893:Anti-Inflammatory Agents; C497106:Atf2 protein, mouse; D020672:I-kappa B Proteins; D015850:Interleukin-6; D008070:Lipopolysaccharides; C000606205:Nfkbia protein, mouse; D010936:Plant Extracts; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; C498144:Rela protein, mouse; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; C482199:lipopolysaccharide, E coli O55-B5; D000072000:NF-KappaB Inhibitor alpha; D048031:JNK Mitogen-Activated Protein Kinases