Green Tea Research Today is a free monthly online journal that collates and summarizes the latest research about Green Tea, including details on benefits, antioxidants, weight loss, diet, side effects. | ||||||||
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Epigallocatechin gallate induces apoptosis of monocytes.Kawai K, Tsuno NH, Kitayama J, Okaji Y, Yazawa K, Asakage M, Sasaki S, Watanabe T, Takahashi K, Nagawa H Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, Japan. kz-kawai@mvd.biglobe.ne.jp BACKGROUND: Monocytes are the main effector cells of the immune system, and the regulation of their survival and apoptosis is essential for monocyte-involved immune responses. Green tea polyphenol catechin has been reported to have antiallergic and anti-inflammatory activities, but its effect on monocytes has not yet been explored. OBJECTIVE: To elucidate the mechanisms of the anti-inflammatory effect of catechin, we studied the effect of catechin, especially epigallocatechin gallate (EGCG), on the apoptosis of monocytes. METHODS: Isolated peripheral blood monocytes were incubated without or with catechin, and apoptosis was evaluated by annexin V and propidium iodide double-staining or terminal deoxynucleotidyl assay. The activation of caspases 3, 8, and 9 was also evaluated by flow cytometry. The influence of GM-CSF or LPS, the known monocyte survival factors, on the EGCG-induced apoptosis of monocytes was investigated. RESULTS: Among the 4 catechin derivatives tested, EGCG and epicatechin gallate induced apoptosis of monocytes. Caspases 3, 8, and 9, which play a central role in the apoptotic cascade, were dose-dependently activated by EGCG treatment. The EGCG-induced apoptosis of monocytes was not affected by GM-CSF or LPS. CONCLUSION: Catechin, especially EGCG, by promoting monocytic apoptosis, may be a new promising anti-inflammatory agent, and should be tested in clinical trials. Published 7 January 2005 in J Allergy Clin Immunol, 115(1): 186-91.
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