Human Nutrition Unit, The φ², Laboratory of Phytochemicals in Physiology, Department of Public Health, University of Parma, Parma, Italy.
Int J Food Sci Nutr. 2012 Aug;63(5):513-21. doi: 10.3109/09637486.2011.640311. Epub 2011 Dec 2.
Green tea is a popular beverage, prepared with infusion of unfermented dried leaves of Camellia sinensis, and is one of the most relevant sources of polyphenolic compounds in the human diet. This study reports green tea flavan-3-ol absorption, metabolism and complete urinary excretion up to 48 h in 20 healthy volunteers. Urinary and tea samples were analysed by high-performance liquid chromatography coupled with tandem mass spectrometry. Green tea contained monomeric flavan-3-ols and proanthocyanidins with a total polyphenol content of 728 μmol. A total of 41 metabolites were identified in urines, all present in conjugated forms. Among these, six colonic metabolites of green tea flavan-3-ols were identified for the first time after green tea consumption in humans. The average 48 h bioavailability was close to 62%, major contributors being microbial metabolites. Some volunteer showed a 100% absorption/excretion, whereas some others were unable to efficiently absorb/excrete this class of flavonoids. This suggests that colonic ring fission metabolism could be relevant in the putative bioactivity of green tea polyphenols.
绿茶是一种受欢迎的饮料，由未发酵的干燥茶树叶子浸泡制成，是人类饮食中多酚化合物的最重要来源之一。本研究报告了 20 名健康志愿者饮用绿茶后 48 小时内的儿茶素类黄酮的吸收、代谢和完全尿排泄情况。通过高效液相色谱-串联质谱法对尿液和茶样进行了分析。绿茶中含有单体儿茶素类黄酮和原花青素，总多酚含量为 728μmol。在尿液中鉴定出了 41 种代谢物，均以结合形式存在。其中，有 6 种是人类饮用绿茶后首次在结肠代谢物中鉴定出的儿茶素类黄酮。平均 48 小时生物利用度接近 62%，主要贡献者是微生物代谢物。一些志愿者的吸收率/排泄率达到 100%，而有些志愿者则无法有效吸收/排泄这类类黄酮。这表明结肠环裂解代谢可能与绿茶多酚的潜在生物活性有关。
