Gingko biloba extract EGb 761 is a suppresser of AP-1 transcription factor stimulated by phorbol 12-myristate 13-acetate.
Transcription factors are activated in response to a wide variety of extracellular stimuli. The present study investigated which step Gingko biloba extract (EGb 761), a flavonoid phytochemical rich preparation can affect signal transduction during AP-1 activation. Kinetic experiments with human Jurkat T-cell lines demonstrate that it takes 1 to 1.5 h to activate AP-1 DNA binding activity. These data indicate that c-fos mRNA is expressed and then AP-1 DNA binding activity is activated. Pretreatment of Jurkat T cells with 10 micrograms/ml EGb 761 suppresses AP-1 DNA activation and c-fos mRNA expression. These results suggest that the step in the signal transduction pathway for AP-1 activation that is inhibited by EGb 761 is upstream to c-fos mRNA expression.
Mizuno
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Department of Molecular and Cell Biology, University of California at Berkeley 94720-3200, USA.
Droy-Lefaix
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MT
Packer
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D002273:Carcinogens / Q000494:pharmacology; D002460:Cell Line; D016166:Free Radical Scavengers / Q000494:pharmacology*; D020441:Ginkgo biloba; D006801:Humans; D010936:Plant Extracts / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013601:T-Lymphocytes / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors*; D000096983:Ginkgo Extract
D002273:Carcinogens; D016166:Free Radical Scavengers; D010936:Plant Extracts; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D013755:Tetradecanoylphorbol Acetate; D018808:Transcription Factor AP-1; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract