Analysis of plasma and urinary tea polyphenols in human subjects.
Analysis of plasma and urinary tea polyphenols in human subjects.
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发表时间：
1995-06
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通讯作者：
Mao-jung Lee;Zhi-Yuan Wang;He Li;Laishun Chen;Yang Sun;Steve Gobbo;D. Balentine;Chung S. Yane
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作者：
Mao-jung Lee;Zhi-Yuan Wang;He Li;Laishun Chen;Yang Sun;Steve Gobbo;D. Balentine;Chung S. Yane
在许多动物模型中，茶已被证明可以抑制化学诱导的肿瘤发生，但喝茶对人类致癌的影响尚不确定。为了开发茶叶消费的生物标志物，我们开发了用高效液相色谱法和coulochem电极阵列检测系统分析人类血浆和尿液样本中的茶多酚的方法。（-）-表没食子儿茶素-3-没食子酸酯（EGCG）、(-)-表没食子儿茶素（EGC）、(-)-表儿茶素-3-没食子酸酯（ECG）和(-)-表儿茶素（EC）是绿茶中的主要多酚。大多数茶多酚在血浆和尿液中以共轭形式存在。将样品与-葡萄糖醛酸酶和硫酸酯酶的混合物孵育，以产生游离形式的茶多酚。经乙酸乙酯萃取，反相色谱分离，根据保留时间和电化学特性对EGCG、EGC和EC进行鉴定。由于检测方式的高选择性，干扰被最小化。茶多酚在较大浓度范围内建立了良好的定量关系。EGCG、EGC、ECG、EC的检出限为0.5 ~ 1.5 ng/ml的血浆或尿样。4名志愿者在温水中饮用1.2 g脱咖啡因绿茶后，1小时采集的血浆样品中EGCG含量为46-268 ng/ml， EGC含量为82-206 ng/ml， EC含量为48-80 ng/ml。血浆样品未检出心电图。尿中EGC和EC的最大排泄发生在3-6小时。
Tea has been shown to inhibit chemically induced tumorigenesis in many animal models, but the effects of tea consumption on human carcinogenesis are not conclusive. In order to develop biomarkers for tea consumption, we developed methods for the analysis of tea polyphenols in human plasma and urine samples using HPLC with the coulochem electrode array detection system. (-)-Epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG), and (-)-epicatechin (EC) are the major polyphenols in green tea. Most of the tea polyphenols were in their conjugated forms in the plasma and urine. The samples were incubated with a mixture of beta-glucuronidase and sulfatase to generate the free form of tea polyphenols. After extraction into ethyl acetate and separation by reversed-phase chromatography, EGCG, EGC, and EC were identified on the basis of their retention times and electrochemical characteristics. Due to the high selectivity of the detection mode, interference was minimized. Good quantitative relationships were established for a large concentration range of tea polyphenols. The limits of detection for EGCG, EGC, ECG, and EC were from 0.5 to 1.5 ng/ml of plasma or urine sample. After ingestion of 1.2 g of decaffeinated green tea in warm water, the plasma samples collected at 1 h from 4 human volunteers contained 46-268 ng/ml of EGCG, 82-206 ng/ml of EGC, and 48-80 ng/ml of EC. ECG was not detected in plasma samples. The maximum urinary excretion of EGC and EC occurred at 3-6 h.(ABSTRACT TRUNCATED AT 250 WORDS)