Boyer Jeanelle, Brown Dan, Liu Rui Hai
Departments of Food Science and Animal Science, Cornell University, Ithaca, New York 14853-7201, USA.
J Agric Food Chem. 2004 Nov 17;52(23):7172-9. doi: 10.1021/jf030733d.
Evidence suggests that regular consumption of fruits and vegetables may reduce the risk of chronic diseases, and phytochemicals from fruits and vegetables may be responsible for this health benefit. However, there is limited knowledge on the bioavailability of specific phytochemicals from whole fruits and vegetables. This study used Caco-2 cells to examine uptake of quercetin aglycon and quercetin 3-glucoside as purified compounds and from whole onion and apple peel extracts. Pure quercetin aglycon was absorbed by the Caco-2 cells in higher concentrations than quercetin 3-glucoside (p < 0.05). Caco-2 cells treated with quercetin 3-glucoside accumulated both quercetin 3-glucoside and quercetin. Caco-2 cells absorbed more onion quercetin aglycon than onion quercetin 3-glucoside (p < 0.05), and the percentage of onion quercetin absorbed was greater than that of pure quercetin, most likely due to enzymatic hydrolysis of quercetin 3-glucoside and other quercetin glucosides found in the onion by the Caco-2 cells. Caco-2 cells absorbed low levels of quercetin 3-glucoside from apple peel extracts, but quercetin aglycon absorption was not detected. Caco-2 cell homogenates demonstrated both lactase and glucosidase activities when incubated with lactose and quercetin 3-glucoside, respectively. This use of the Caco2 cell model appears to be a simple and useful system for studying bioavailability of whole food phytochemicals and may be used to assess differences in bioavailability between foods.
有证据表明，经常食用水果和蔬菜可能会降低患慢性病的风险，水果和蔬菜中的植物化学物质可能是这种健康益处的原因。然而，对于来自完整水果和蔬菜的特定植物化学物质的生物利用度，人们了解有限。本研究使用Caco-2细胞来检测槲皮素苷元以及槲皮素3-葡萄糖苷作为纯化化合物，以及从完整洋葱和苹果皮提取物中的摄取情况。与槲皮素3-葡萄糖苷相比，Caco-2细胞吸收的纯槲皮素苷元浓度更高（p < 0.05）。用槲皮素3-葡萄糖苷处理的Caco-2细胞同时积累了槲皮素3-葡萄糖苷和槲皮素。Caco-2细胞吸收的洋葱槲皮素苷元比洋葱槲皮素3-葡萄糖苷更多（p < 0.05），并且洋葱中吸收的槲皮素百分比高于纯槲皮素，这很可能是由于Caco-2细胞对洋葱中存在的槲皮素3-葡萄糖苷和其他槲皮素糖苷进行了酶促水解。Caco-2细胞从苹果皮提取物中吸收的槲皮素3-葡萄糖苷水平较低，但未检测到槲皮素苷元的吸收。当分别与乳糖和槲皮素3-葡萄糖苷孵育时，Caco-2细胞匀浆显示出乳糖酶和葡萄糖苷酶活性。使用Caco2细胞模型似乎是研究全食物植物化学物质生物利用度的一种简单而有用的系统，可用于评估不同食物之间生物利用度的差异。
