物谷報道：根據(jù)Arizona癌癥中心的研究結果,，綠茶中富含的化學物質能大大促進一類關鍵解毒酶的產生,，特別是對于那些缺少這類有益蛋白的人而言。
以上結果發(fā)表在8月的Cancer Epidemiology, Biomarkers & Prevention上,，它表明綠茶中的物質可以強化人們對抗造成癌癥毒素的能力,。在針對42人的研究中，小組發(fā)現(xiàn)富含物——相當于8-16杯綠茶中含有的綠茶酚——提高了酶產量達80%,，這一酶屬于谷胱甘肽S轉移酶（GST）,。
項目負責人，Arizona大學副教授H. H. Sherry Chow發(fā)現(xiàn),，GST對于身體對抗造成癌癥的化學物質等很重要,。科學家長期以來對綠茶很感興趣,，因為他們發(fā)現(xiàn)經常飲用綠茶的人群,，例如中國人和日本人患癌癥的幾率更低。為了確認綠茶能對抗癌癥,，NCI支持了一系列科學研究,。
而此項研究則主要用來分析綠茶酚是否對健康人的GST酶水平有影響，從而解釋其抗癌作用,。首先志愿者被要求戒茶4周，以確定每人的GST基線,。然后志愿者被要求每天清晨空腹服用4個含Polyphenon E的膠囊,，一共含有800毫克EGCG，4周后再檢測血液,，其間不能喝茶以及食用其它十字花科蔬菜,。
結果發(fā)現(xiàn)，Polyphenon E能提高所有參與實驗的志愿者的GST活躍性,，但是其中作用最明顯的是對于那些在血液基線的測量中表現(xiàn)出較低GST活性的志愿者——相比GST基準它們提高了80%,。Chow說：“這是首次通過臨床實驗證實綠茶物質能增加人體的解毒酶，或許還有其它綠茶抗癌的機制,，但無論如何這是一個好的開始,。” （教育部科技發(fā)展中心）
原文鏈接：http://www.physorg.com/news105966521.html
原始出處:
Cancer Epidemiology Biomarkers & Prevention 16, 1662-1666, August 1, 2007. doi: 10.1158/1055-9965.EPI-06-0830
Modulation of Human Glutathione S-Transferases by Polyphenon E Intervention
H.-H. Sherry Chow1, Iman A. Hakim1, Donna R. Vining1, James A. Crowell3, Margaret E. Tome2, James Ranger-Moore1, Catherine A. Cordova1, Dalia M. Mikhael1, Margaret M. Briehl2 and David S. Alberts1
1 Arizona Cancer Center and 2 Department of Pathology, The University of Arizona, Tucson, Arizona and 3 Division of Cancer Prevention, National Cancer Institute, Bethesda, Maryland
Requests for reprints: H.-H. Sherry Chow, Arizona Cancer Center, The University of Arizona, Tucson, AZ 85724. Phone: 520-626-3358; Fax: 520-626-5348. E-mail: [email protected]
Purpose: Green tea consumption has been associated with decreased risk of certain types of cancers in humans. Induction of detoxification enzymes has been suggested as one of the biochemical mechanisms responsible for the cancer-preventive effect of green tea. We conducted this clinical study to determine the effect of repeated green tea polyphenol administration on a major group of detoxification enzymes, glutathione S-transferases (GST).
Methods: A total of 42 healthy volunteers underwent a 4-week washout period by refraining from tea or tea-related products. At the end of the washout period, a fasting blood sample was collected, and plasma and lymphocytes were isolated for assessment of GST activity and level. Following the baseline evaluation, study participants underwent 4 weeks of green tea polyphenol intervention in the form of a standardized Polyphenon E preparation at a dose that contains 800 mg epigallocatechin gallate (EGCG) once a day. Polyphenon E was taken on an empty stomach to optimize the oral bioavailability of EGCG. Upon completion of the intervention, samples were collected for postintervention GST assessment.
