Human studies on the absorption, distribution, metabolism, and excretion of tea polyphenols
Human studies on the absorption, distribution, metabolism, and excretion of tea polyphenols
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DOI：
10.3945/ajcn.113.058958
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发表时间：
2013-12-01
影响因子：
7.1
通讯作者：
Crozier, Alan
中科院分区：
文献类型：
--
作者：
Clifford, Michael N.;van der Hooft, Justin J. J.;Crozier, Alan
综述了近年来人们饮用绿色茶后黄烷-3-醇类化合物生物利用度的研究进展。（表）儿茶素和（表）没食子儿茶素葡萄糖醛酸苷的葡萄糖醛酸苷、硫酸盐和甲基代谢物在摄入后1.6-2.3 h达到峰值纳摩尔/升血浆浓度，表明在小肠中吸收。然后浓度下降，只有微量残留8小时后摄入。尿排泄的代谢物超过24小时后，绿色茶消费对应的28.5%的摄入（表）儿茶素和11.4%的（表）没食子儿茶素，这表明更高的吸收比大多数其他类黄酮。绿色茶中主要的黄烷-3-醇（-）-表儿茶素-3-O-没食子酸酯的命运尚不清楚，因为它在血浆中以低浓度出现未代谢，但不经尿液排泄。黄烷-3-醇可能的肝肠再循环进行了讨论，沿着剂量和其他食物成分对黄烷-3-醇生物利用度的影响。大约三分之二摄入的黄烷-3-醇从小肠进入大肠，在大肠中微生物群的作用导致它们转化为C-6-C-5苯基戊内酯和苯基戊酸，其经历侧链缩短以产生C-6-C-1酚酸和芳香酸，其进入血液并以相当于黄烷-3-醇摄入量的36%的量在尿液中排泄。其中一些结肠来源的catalysts可能在体内茶消费的潜在保护作用中发挥作用。虽然含有茶黄素和茶红素的红茶在西方世界被广泛消费，但令人惊讶的是，关于摄入后这些化合物的吸收和代谢及其对健康的潜在影响的研究很少。
Recent research on the bioavailability of flavan-3-ols after ingestion of green tea by humans is reviewed. Glucuronide, sulfate, and methyl metabolites of (epi)catechin and (epi)gallocatechin glucuronide reach peak nanomolar per liter plasma concentrations 1.6-2.3 h after intake, indicating absorption in the small intestine. The concentrations then decline, and only trace amounts remain 8 h after ingestion. Urinary excretion of metabolites over a 24-h period after green tea consumption corresponded to 28.5% of the ingested (epi) catechin and 11.4% of (epi)gallocatechin, suggesting higher absorption than that of most other flavonoids. The fate of (-)-epicatechin-3-O-gallate, the main flavan-3-ol in green tea, is unclear because it appears unmetabolized in low concentrations in plasma but is not excreted in urine. Possible enterohepatic recirculation of flavan-3-ols is discussed along with the impact of dose and other food components on flavan-3-ol bioavailability. Approximately two-thirds of the ingested flavan-3-ols pass from the small to the large intestine where the action of the microbiota results in their conversion to C-6-C-5 phenylvalerolactones and phenylvaleric acids, which undergo side-chain shortening to produce C-6-C-1 phenolic and aromatic acids that enter the bloodstream and are excreted in urine in amounts equivalent to 36% of flavan-3-ol intake. Some of these colon-derived catabolites may have a role in vivo in the potential protective effects of tea consumption. Although black tea, which contains theaflavins and thearubigins, is widely consumed in the Western world, there is surprisingly little research on the absorption and metabolism of these compounds after ingestion and their potential impact on health.