Walgren R A, Walle U K, Walle T
Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425, USA.
Biochem Pharmacol. 1998 May 15;55(10):1721-7. doi: 10.1016/s0006-2952(98)00048-3.
There is mounting evidence from human epidemiological, animal in vivo, and in vitro studies to suggest beneficial effects related to the consumption of quercetin and its glucosides. However, there is limited knowledge on the oral bioavailability of these natural products. This study examined the intestinal epithelial membrane transport of quercetin, quercetin 4'-glucoside, and quercetin 3,4'-diglucoside, using the Caco-2 human colonic cell line, a model of human intestinal absorption. The apparent permeability (Papp) of each agent was measured in both apical to basal and basal to apical directions. The apical to basolateral flux of quercetin, Papp 5.8 +/- 1.1 x 10(-6) cm x sec(-1) (mean +/- SEM), was more than 10-fold higher than for the paracellular transport marker mannitol, 0.48 +/- 0.09 x 10(-6) cm x sec(-1) (P < 0.01). Under identical conditions, the Papp for the transcellular marker propranolol was about 5-fold higher than for quercetin (P < 0.001). Interestingly, the reverse, basolateral to apical, flux of quercetin (Papp 11.1 +/- 1.2 x 10(-6) cm x sec(-1)) was almost 2-fold higher than the apical to basolateral flux (P < 0.001). In similar experiments, quercetin 4'-glucoside demonstrated no absorption, Papp < 0.02 x 10(-6) cm x sec(-1) in the apical to basal direction, but did demonstrate basal to apical flux, Papp 1.6 +/- 0.2 x 10(-6) cm x sec(-1). Quercetin 3,4'-diglucoside showed a low apical to basolateral transport (Papp 0.09 +/- 0.03 x 10(-6) cm x sec(-1)); its reverse, basolateral to apical, transport was, however, 4-fold higher (P < 0.05). In these cells, glucose was actively transported with an apical to basolateral Papp of 36.8 +/- 1.1 x 10(-6) cm x sec(-1). These observations suggest facile absorption of quercetin through the human intestinal epithelium, but contrary to a previous proposal, they do not support an active transport process for quercetin glucosides.
来自人类流行病学、动物体内和体外研究的证据越来越多，表明食用槲皮素及其糖苷具有有益效果。然而，关于这些天然产物的口服生物利用度的了解有限。本研究使用Caco-2人结肠细胞系（一种人类肠道吸收模型），研究了槲皮素、槲皮素4'-葡萄糖苷和槲皮素3,4'-二葡萄糖苷的肠上皮膜转运。在顶端到基底和基底到顶端两个方向上测量了每种物质的表观渗透率（Papp）。槲皮素从顶端到基底的通量，Papp为5.8±1.1×10⁻⁶ cm×sec⁻¹（平均值±标准误），比细胞旁转运标记物甘露醇（0.48±0.09×10⁻⁶ cm×sec⁻¹）高10倍以上（P<0.01）。在相同条件下，跨细胞标记物普萘洛尔的Papp比槲皮素高约5倍（P<0.001）。有趣的是，槲皮素从基底到顶端的反向通量（Papp为11.1±1.2×10⁻⁶ cm×sec⁻¹）几乎是从顶端到基底通量的2倍（P<0.001）。在类似实验中，槲皮素4'-葡萄糖苷在顶端到基底方向上没有吸收，Papp<0.02×10⁻⁶ cm×sec⁻¹，但在基底到顶端方向上有通量，Papp为1.6±0.2×10⁻⁶ cm×sec⁻¹。槲皮素3,4'-二葡萄糖苷显示出较低的顶端到基底转运（Papp为0.09±0.03×10⁻⁶ cm×sec⁻¹）；然而，其反向运输（基底到顶端）则高4倍（P<0.05）。在这些细胞中，葡萄糖的主动转运的顶端到基底Papp为36.8±1.1×10⁻⁶ cm×sec⁻¹。这些观察结果表明槲皮素可通过人肠道上皮轻松吸收，但与先前的提议相反，它们不支持槲皮素糖苷的主动转运过程。
