Suppression of tissue necrosis factor-alpha or hydrogen peroxide-activated primary human T lymphocytes by Ginkgo biloba extract through down-regulation of activator protein-1 signal transduction.
OBJECTIVE
It was unknown whether Ginkgo biloba extract has regulatory effects on human T lymphocytes activated by tissue necrosis factor-alpha (TNF-alpha), which has an important role on the progression of inflammatory atherosclerotic plaques. We evaluated the effects of G. biloba extract on activated human peripheral T lymphocytes, which were isolated from human whole blood.


METHODS
The human T lymphocytes were treated with 25-100 microg G. biloba extract for 2h first. Then they were activated by TNF-alpha and H(2)O(2) to investigate the modulatory effects of G. biloba extract on human T lymphocytes. Electrophoretic mobility shift assay, Western blot (Immunoblot) analysis and immunoprecipitation kinase assays were used.


RESULTS
The inhibition of activated human T lymphocyte specifically correlated with the down-regulation of AP-1 DNA-binding activities. G. biloba extract was unique in its ability to inhibit the activation of c-Jun NH2-terminal protein kinase.


CONCLUSIONS
G. biloba extract might have its novel therapeutic effects on inflammation-based atherosclerotic diseases.
Tsao
Tien-Ping
TP
Division of Cardiology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan, ROC.
Lai
Jenn-Haung
JH
Yang
Shih-Ping
SP
Ho
Ling-Jun
LJ
Liou
Jun-Ting
JT
Cheng
Cheng-Chung
CC
Cheng
Shu-Meng
SM
D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015536:Down-Regulation; D024202:Electrophoretic Mobility Shift Assay; D020441:Ginkgo biloba / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D008213:Lymphocyte Activation; D010936:Plant Extracts / Q000494:pharmacology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D010936:Plant Extracts; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide; D048031:JNK Mitogen-Activated Protein Kinases