Echinacea alkylamides modulate TNF-α gene expression via cannabinoid receptor CB2 and multiple signal transduction pathways

• Published in: FEBS letters 2004-11, Vol.577 (3), p.563-569
• Main Authors: Gertsch, Juerg, Schoop, Roland, Kuenzle, Urs, Suter, Andy
• Format: Article
• Language: English
• Subjects: Alkylamide; ATF-2, activating transcription factor-2; cAMP, cyclic adenosine monophosphate; Cannabinoid receptor CB2; CB2, cannabinoid receptor 2; Cells, Cultured; CREB-1, cAMP responsive element binding protein-1; Cyclic AMP - metabolism; Dose-Response Relationship, Drug; Echinacea; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Gene Expression Regulation - drug effects; GM-CSF, granulocyte colony stimulating factor; Humans; Immunomodulation; JNK Mitogen-Activated Protein Kinases - metabolism; JNK, Jun N-terminal kinase; Kinetics; Leukocytes, Mononuclear - drug effects; Lipopolysaccharides - pharmacology; LPS, lipopolysaccharide; Macrophages - drug effects; MAPK, mitogen-activated protein kinase; Molecular Structure; Mφs, macrophages; NF-AT, nuclear factor of activated T-cells; NF-kappa B - metabolism; NF-κB, nuclear factor κB; NK-cells, natural killer cells; p38 Mitogen-Activated Protein Kinases - metabolism; PBMCs, peripheral blood mononuclear cells; Plant Extracts - chemistry; Plant Extracts - pharmacology; RANTES, regulated upon activation, normal T-cell expressed and secreted; Receptor, Cannabinoid, CB2 - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - analysis; RNA, Messenger - metabolism; Signal Transduction; STAT-4, signal transducer and activator of transcription-4; TNF-α, tumor necrosis factor α; Tumor necrosis factor α; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor Necrosis Factor-alpha - metabolism; Up-Regulation
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/j.febslet.2004.10.064

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 TM and found that it induced de novo synthesis of tumor necrosis factor α (TNF-α) mRNA in primary human monocytes/macrophages, but not TNF-α protein. Moreover, LPS-stimulated TNF-α 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-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides (1/2), trienoic (3) and dienoic acid (4) derivatives are responsible for this effect. The upregulation of TNF-α mRNA was found to be mediated by CB2 receptors, increased cAMP, p38/MAPK and JNK signaling, as well as NF-κB 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.