Echinacea alkylamides modulate TNF-alpha gene expression via cannabinoid receptor CB2 and multiple signal transduction pathways.
Echinacea plant preparations are widely used in the prevention and treatment of common cold. However, so far no molecular mechanism of action has been proposed. We analyzed the standardized tincture Echinaforce and found that it induced de novo synthesis of tumor necrosis factor alpha (TNF-alpha) mRNA in primary human monocytes/macrophages, but not TNF-alpha protein. Moreover, LPS-stimulated TNF-alpha protein was potently inhibited in the early phase but prolonged in the late phase. A study of the main constituents of the extract showed that the alkylamides dodeca-2E,4E,8Z,10E/Z-tetraenoic acid isobutylamides (1/2), trienoic (3) and dienoic acid (4) derivatives are responsible for this effect. The upregulation of TNF-alpha mRNA was found to be mediated by CB2 receptors, increased cAMP, p38/MAPK and JNK signaling, as well as NF-kappaB and ATF-2/CREB-1 activation. This study is the first to report a possible molecular mechanism of action of Echinacea, highlighting the role of alkylamides as potent immunomodulators and potential ligands for CB2 receptors.
Gertsch
Juerg
J
Swiss Federal Institute of Technology, Institute of Pharmaceutical Sciences, Wolfgang-Pauli-Str. 10 CH-8093 Zürich, Switzerland. juerg.gertsch@pharma.ethz.ch
Schoop
Roland
R
Kuenzle
Urs
U
Suter
Andy
A
D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020900:Echinacea; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D007700:Kinetics; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects; D015394:Molecular Structure; D016328:NF-kappa B / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D043885:Receptor, Cannabinoid, CB2 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D008070:Lipopolysaccharides; D016328:NF-kappa B; D010936:Plant Extracts; D012333:RNA, Messenger; D043885:Receptor, Cannabinoid, CB2; D014409:Tumor Necrosis Factor-alpha; D000242:Cyclic AMP; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases