BACKGROUND Quercetin and quercetin glycosides are widely consumed flavonoids found in many fruits and vegetables. These compounds have a wide range of potential health benefits, and understanding the bioavailability of flavonoids from foods is becoming increasingly important. METHODS This study combined an in vitro digestion, a lactase treatment and the Caco-2 cell model to examine quercetin ...

Flavonoids are assumed to exert beneficial effects in different types of cancers at high concentrations. Yet, their molecular mechanisms of action remain unknown. The present study aimed to examine the effect of quercetin on proliferation and apoptosis in HER2-expressing breast cancer cells. The anti-proliferative effects of quercetin were examined by proliferation, MTT and clonogenic survival ...

Previous research indicates that ultramarathon exercise can result in blood oxidative stress. The purpose of this investigation was to examine the efficacy of oral supplementation with quercetin, a naturally occurring compound with known antioxidant properties, as a potential countermeasure against blood oxidative stress during an ultramarathon competition. In double-blind fashion, 63 participa...

The effect of quercetin, a flavonoid found in many plants, on the proliferation of human leukemic T-cells was analyzed. Quercetin reversibly blocked the cell cycle at a point 3-6 h before the start of DNA synthesis. Expression of the growth-related genes histone H4, cyclin A and B, and p34 ~dc2 was suppressed in cells blocked with quercetin. Comparison of the quercetin arrest points with those ...

Chronic ingestion of apple pectin has been shown to increase the absorption of quercetin in rats. The present study was designed to elucidate whether the simultaneous ingestion of quercetin with apple pectin could enhance the absorption of quercetin in humans, and the effects of dose dependency and degree of pectin methylation on quercetin absorption were also investigated. Healthy volunteers (...

Accumulated data have suggested that the hydroxyl groups of flavonoids are important for their bioactive function. To directly demonstrate the role of hydroxyl groups, we synthesized a derivative of quercetin, 3,7,3',4'-O-tetrabenzylquercetin (4Bn-Q) that substituted the hydroxyl groups of quercetin with benzyl groups, and then evaluated the ability to inhibit cell proliferation and cause apopt...

A purification and fractionation process of the edible flowers Tibouchina mollis urvilleana followed by first attempt to anthocyanin flavonol characterisation identification UHPLC-DAD-ESI-MS were developed. T. exhibited a higher monomeric content, mainly due presence 3-O-(6′-p-coumaroyl)-glucoside derivatives malvidin petunidin. Quercetin-3-O-hexoside was major identified in urvilleana, lack my...

PURPOSE To investigate the effect of quercetin on the reversal of tamoxifen resistance in breast cancer cells, and explore the underlying mechanism. METHODS We established a tamoxifen-resistant breast cancer cell line (MCF-7Ca/TAM-R), and exposed it to different concentrations of quercetin (experimental group 1: 10 μM, group 2: 25 μM, and group 3: 50μM). Each group was further subdivided into...

Effects of quercetin, a kind of flavonoids, on the vasodilating actions were investigated. Among the mechanisms for quercetin-induced vasodilatation in rat aorta, the involvement with the Ca(2+) activated K(+) (K(Ca)) channel was examined. Pretreatment with NE (5 microM) or KCl (60 mM) was carried out and then, the modulation by quercetin of the constriction was examined using rat aorta ring st...

The detailed investigation of a methanolic extract of aerial parts of Achillea nobilis resulted in the isolation of 10 flavonoids. A new C-glycosylflavone, luteolin-6-C-apiofuranosyl-(1'''-->2'')-glucoside, was isolated besides orientin, isoorientin, vitexin, isoschaftoside, luteolin-7-O-beta-glucuronide, luteolin-4'-O-beta-glucoside and quercetin-3-O-methyl ether and two rare flavonolglycoside...