Antioxidant and Angiogenesis Effects of Green Tea vs Epigallocatechin-3-gallate

绿茶与表没食子儿茶素-3-没食子酸酯的抗氧化和血管生成作用

• 批准号: 6666252
• 负责人: MAI BROOKS
• 金额: $ 15.92万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6666252
• 关键词: DNA damage; alternative medicine; antineoplastics; antioxidants; clinical research; dietary supplements; drug discovery /isolation; flavonoids; free radical oxygen; human subject; male; nutrition related tag; peroxidation; pharmacokinetics; plant extracts; tea

DESCRIPTION: Cancer is the second most common disease related cause of death in the USA. A combination of epidemiological and basic science evidence strongly suggests that diet and plant-derived phytochemicals may play an important role in cancer prevention. Thus, there is an urgent need for research on phytochemicals which may prevent cancer or which may be useful adjuncts in the prevention of cancer recurrence among successfully treated cancer survivors where prevention of cancer recurrence is vital. Green Tea contains potent antioxidants called polyphenols that have been shown to reduce tumor growth and metastasis capacity and angiogenesis in several studies. The four major catechins in green tea are: (-)-epicatecchin, (-)-epicatechin-3-gallate, (-)-epigallocatechin, and (-)-epigallocatechin-3-gallate (EGCG). EGCG is the main component, accounting for 40% of the total polypenolic mixture, but it is not clear that this is the only component important in the action of green tea. Preliminary work suggests that these polyphenols protect DNA more than either Vitamin E or beta-carotene in the retro-Ames assay. Anti-angiogenic strategies differ from other therapeutic agents because they are based on static effects on tumors and require prolonged administration. Dietary supplements such as green tea would be perhaps useful alone or in combination of other anti-angiogenic agents. The studies outlined in this proposal are aimed to compare the activities of standardized Green tea extracts and purified EGCG to provide a critical scientific support for future clinical studies of green tea dietary supplements versus proceeding with EGCG. Thus, the aims are: To compare EGCG with green tea catechin extract, examining DNA protection, and tumor cell growth. This aim will determine whether the antioxidant and DNA protective effects of green tea are due to other constituents other than ECGC. To compare anti-angiogenic potency of EGCG and green tea extract in vitro and in vivo. This aim will determine whether the growth inhibitory effects induced by green tea are due to EGCG or to additional catechins in the green tea mixture. To compare the bioavailability and antioxidant bioactivity of EGCG and mixed green tea catechins by measuring polyphenols, oxygen radical absorbing capacity (ORAC), lipid peroxidation, and white cell DNA base damage in timed blood samples from normal volunteers.

描述：癌症是第二大常见疾病相关死亡原因 美国。流行病学和基础科学证据的结合有力 表明饮食和植物源性植物化学物质可能发挥重要作用 在癌症预防方面。因此，迫切需要研究 可以预防癌症或可能是有用的辅助剂的植物化学物质 预防成功治疗的癌症幸存者的癌症复发 预防癌症复发至关重要。绿茶含有强效 称为多酚的抗氧化剂已被证明可以减少肿瘤生长 多项研究中的转移能力和血管生成。 绿茶中的四种主要儿茶素是：(-)-表儿茶素、 (-)-表儿茶素-3-没食子酸酯、(-)-表没食子儿茶素，和 (-)-表没食子儿茶素-3-没食子酸酯 (EGCG)。主要成分为EGCG，占 占总多酚混合物的 40%，但尚不清楚这就是 绿茶作用中唯一重要的成分。初步工作表明 这些多酚比维生素 E 或 β-胡萝卜素更能保护 DNA 在逆艾姆斯测定中。抗血管生成策略不同于其他策略 治疗剂，因为它们基于对肿瘤的静态作用 需要长期服用。绿茶等膳食补充剂会 可以单独使用或与其他抗血管生成剂组合使用。 本提案中概述的研究旨在比较 标准化绿茶提取物和纯化 EGCG 提供关键的 为绿茶膳食补充剂未来临床研究提供科学支持 与继续使用 EGCG 相比。因此，目标是： 比较 EGCG 与绿茶儿茶素提取物，检查 DNA 保护，以及 肿瘤细胞生长。这个目标将决定抗氧化剂和 DNA 是否 绿茶的保护作用是由于 ECGC 以外的其他成分。 比较 EGCG 和绿茶提取物的体外抗血管生成功效 体内。该目标将确定生长抑制作用是否引起 绿茶中的 EGCG 或绿茶中额外的儿茶素 混合物。 比较 EGCG 和混合制剂的生物利用度和抗氧化生物活性 通过测量绿茶儿茶素多酚、氧自由基吸收能力 (ORAC)、脂质过氧化和定时血液中白细胞 DNA 碱基损伤 样本取自正常志愿者。