Tanaka Seiya, Oyama Manami, Nishikawa Miyu, Ikushiro Shinichi, Hara Hiroshi
a Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan.
b Department of Biotechnology, Faculty of Engineering , Toyama Prefectural University , Imizu , Japan.
Biosci Biotechnol Biochem. 2018 Dec;82(12):2118-2129. doi: 10.1080/09168451.2018.1515615. Epub 2018 Sep 10.
Quercetin is a flavonoid with many physiological effects. Absorbed quercetin is rapidly conjugated in the intestinal epithelium and liver. Different positional isomers of quercetin conjugates have different physiological properties. However, the mechanisms of quercetin conjugation in the intestine are not fully clarified. We examined the regioselective quercetin conjugate formation in the intestine after oral administration of quercetin glycosides, by simultaneous sampling of blood from the portal vein and superior vena cava, and quantifying various positional isomers of quercetin glucuronides and sulfates in conscious rats. Concentrations of quercetin glucuronides were higher in blood from the portal vein than the superior vena cava, showing that glucuronidation mainly occurred in the intestine. Such differences were not observed for quercetin sulfates. Regioselectivity of the intestinal glucuronidation in quercetin hydroxyl groups were 7- >3'- >3- >4'-OH. Quercetin was mainly sulfated on 3'-OH at 30 min, but on 4'-OH at 240 min.
槲皮素是一种具有多种生理效应的黄酮类化合物。被吸收的槲皮素在肠上皮和肝脏中迅速结合。槲皮素结合物的不同位置异构体具有不同的生理特性。然而，槲皮素在肠道中的结合机制尚未完全阐明。我们通过同时从门静脉和上腔静脉采集血液，并对清醒大鼠体内槲皮素葡萄糖醛酸苷和硫酸盐的各种位置异构体进行定量，研究了口服槲皮素糖苷后肠道中区域选择性槲皮素结合物的形成。门静脉血中槲皮素葡萄糖醛酸苷的浓度高于上腔静脉血，表明葡萄糖醛酸化主要发生在肠道。槲皮素硫酸盐未观察到这种差异。槲皮素羟基在肠道葡萄糖醛酸化的区域选择性为7->3’->3->4’-OH。槲皮素在30分钟时主要在3’-OH上硫酸化，但在240分钟时在4’-OH上硫酸化。
