Plant Products and Human Nutrition Group, Graham Kerr Building, Division of Ecology and Evolutionary Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
J Agric Food Chem. 2010 Jan 27;58(2):1296-304. doi: 10.1021/jf9032975.
Following the ingestion of green tea, substantial quantities of flavan-3-ols pass from the small to the large intestine (Stalmach et al. Mol. Nutr. Food Res. 2009, 53, S44-S53; Mol. Nutr. Food Res. 2009, doi: 10.1002/mnfr.200900194). To investigate the fate of the flavan-3-ols entering the large intestine, where they are subjected to the action of the colonic microflora, (-)-epicatechin, (-)-epigallocatechin, and (-)-epigallocatechin-3-O-gallate were incubated in vitro with fecal slurries and the production of phenolic acid catabolites was determined by GC-MS. In addition, urinary excretion of phenolic catabolites was investigated over a 24 h period after ingestion of either green tea or water by healthy volunteers with a functioning colon. The green tea was also fed to ileostomists, and 0-24 h urinary excretion of phenolic acid catabolites was monitored. Pathways are proposed for the degradation of green tea flavan-3-ols in the colon and further catabolism of phenolic compounds passing into the circulatory system from the large intestine, prior to urinary excretion in quantities corresponding to ca. 40% of intake compared with ca. 8% absorption of flavan-3-ol methyl, glucuronide, and sulfate metabolites in the small intestine. The data obtained point to the importance of the colonic microflora in the overall bioavailability and potential bioactivity of dietary flavonoids.
摄入绿茶后，大量的黄烷-3-醇从小肠转移到大肠（Stalmach 等人，《分子营养与食品研究》2009 年，53 期，S44-S53；《分子营养与食品研究》2009 年，doi：10.1002/mnfr.200900194）。为了研究进入大肠的黄烷-3-醇的命运，它们在大肠中受到结肠微生物群的作用，将（-）-表儿茶素、（-）-表没食子儿茶素和（-）-表没食子儿茶素-3-O-没食子酸酯与粪便悬浮液在体外孵育，并通过 GC-MS 确定酚酸代谢产物的产生。此外，通过对具有正常结肠的健康志愿者在摄入绿茶或水后 24 小时内的尿液排泄酚类代谢物进行研究。还将绿茶喂给回肠造口术患者，并监测酚酸代谢物在 0-24 小时内的尿液排泄。提出了在结肠中降解绿茶黄烷-3-醇的途径，以及进一步代谢从大肠进入循环系统的酚类化合物，然后在尿液中排泄，排泄量与摄入量的 40%左右相对应，而在小肠中，黄烷-3-醇甲基、葡萄糖醛酸和硫酸盐代谢物的吸收率约为 8%。获得的数据表明了结肠微生物群在饮食类黄酮的整体生物利用度和潜在生物活性中的重要性。
