Uptake of Quercetin and Quercetin 3-Glucoside from Whole Onion and Apple Peel Extracts by Caco-2 Cell Monolayers

Abstract

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.

Induction of Cell Cycle Arrest and Apoptosis by Ormenis Eriolepis a Morrocan Endemic Plant in Various Human Cancer Cell Lines

“…Numerous studies have described the cancer preventive effects and molecular mechanisms of quercetin, which has been shown to one of the major flavonoids with antiproliferative efficacy on a wide range of cancer cells (Boyer et al, 2004;Kang and Liang, 1997;Suh et al, 2010). For example, quercetin was shown to inhibit the growth of acute lymphoid and myeloid leukemia cells (Kang and Liang, 1997).…”

Quercetin potentiates the effect of γδ T cells via modulating the expressions of Granzyme B, perforin and IFN-γ and also regulates the Wnt/β-catenin signalling pathway in human colon cancer cells

“…Much of the health effects of fruits and vegetables have been attributed to phytochemicals as flavonoids (Ames et al, 1993;Boyer et al, 2004).…”

Effect of Natural Products with Cancer Chemopreventive Agents on Endogenous Antioxidant Enzymes in the Liver of Albino Mice

“…Epidemiological studies have shown that the ingestion of diet rich in fruit and vegetable may decrease the risk of cancer ( (Steinmetz andPotter, 1991,1996;Block et al, 1992& Jeanelle et al;2004). Much of the protective effects of fruits and vegetable have been attributed to phytochemicals with the ability to protect against oxidative stress induced damage (Nakazawa and Oshizawa, 1998).…”

“…Much of the protective effects of fruits and vegetable have been attributed to phytochemicals with the ability to protect against oxidative stress induced damage (Nakazawa and Oshizawa, 1998). The chemopreventive agents commonly found in fruits and vegetables are mainly flavonoids such as Quercetin found in (Allium cepa) (Boyer et al, 2004), Indole -3 -carbinol in Brassica oleracea (Brandi et al, 2005). Epigallo catechin gallatte (EGCG) in green tea and caffeic acid phenethyl ester in honey (Cavine et al;2006).…”