Unilever R&D, Vlaardingen, The Netherlands.
Drug Delivery and Disposition, Gasthuisberg O&N II, KU Leuven, Leuven, Belgium.
J Pharm Pharmacol. 2018 Aug;70(8):1002-1008. doi: 10.1111/jphp.12929. Epub 2018 May 15.
Quercetin is one of the main dietary flavonoids and undergoes a substantial intestinal phase-II metabolism. Quercetin conjugates have been detected in plasma and in urine, but their presence in the small intestine has not been assessed. This study aimed to investigate the intestinal metabolism and metabolite excretion of quercetin by the human small intestinal wall after oral dosing.
Six healthy volunteers were given a capsule of 500 mg of quercetin with 240 ml of water. Duodenal fluids were collected using the intraluminal sampling technique for 4 h and analysed by LC-MS/MS.
Phase-II metabolites of quercetin were detected and quantified in aspirated intestinal fluids. Metabolites appeared almost immediately after administration, indicating an intestinal metabolism and apical excretion into the lumen. Quercetin-3'-O-glucuronide was found to be the main intestinal metabolite. Our results could not conclude on the enterohepatic recycling of quercetin or its metabolites, although several individual profiles showed distinctive peaks.
This study highlights the intestinal metabolism and excretion of quercetin and its conjugates in humans and gives insights into the relevant concentrations which should be used to investigate potential food-drug interactions in vitro.
槲皮素是主要的饮食类黄酮之一，会在肠道中经历大量的二期代谢。已在血浆和尿液中检测到槲皮素的共轭物，但尚未评估其在小肠中的存在。本研究旨在调查口服给予 500mg 槲皮素胶囊后，人体小肠壁对槲皮素的肠道代谢和代谢产物排泄情况。
6 名健康志愿者用水服下 500mg 槲皮素胶囊。采用腔内采样技术采集 4 小时的十二指肠液，并通过 LC-MS/MS 进行分析。
在抽吸的肠液中检测到并定量了槲皮素的二期代谢物。代谢物在给药后几乎立即出现，表明存在肠道代谢和顶端排泄到肠腔中。槲皮素-3'-O-葡萄糖醛酸苷被发现是主要的肠道代谢物。我们的结果无法得出关于槲皮素或其代谢物的肠肝循环的结论，尽管一些个体图谱显示出独特的峰。
本研究强调了槲皮素及其共轭物在人体中的肠道代谢和排泄，并为研究体外潜在的食物-药物相互作用提供了相关的浓度参考。
