Flavonoids are synthesized in response to developmental and environmental signals and perform many functions in plants. Arabidopsis (Arabidopsis thaliana) roots grown in complete darkness do not accumulate flavonoids since the expression of genes encoding enzymes of flavonoid biosynthesis is light dependent. Yet, flavonoids accumulate in root tips of plants with light-grown shoots and light-shi...

Major brands of cocoa powder products present in the Spanish market were analyzed for monomeric flavanols [(+)-catechin and (-)-epicatechin] and flavonols [quercetin-3-glucuronide, quercetin-3-glucoside (isoquercitrin), quercetin-3-arabinoside, and quercetin]. In addition, the influence of the manufacturing process of cocoa powder products, in particular, the alkalinization treatment ( Dutching...

Flavonoids are phytochemicals that are widespread in the human diet. Despite limitations in their bioavailability, experimental and epidemiological data suggest health benefits of flavonoid consumption. Valid biomarkers of flavonoid intake may be useful for estimating exposure in a range of settings. However, to date, few useful flavonoid biomarkers have been identified. In this study, we used ...

Quercetin is a flavonoid compound found in a number of medicinal plants that are often prescribed in Chinese clinics for the treatment of cardiovascular diseases. The present study investigated the effects of quercetin on chronic cerebral ischemia in rats produced through bilateral occlusion of the carotid arteries. Treatment of quercetin (5 mg/kg i.p. for 14 days) was found to improve the perf...

The natural flavonoid quercetin is known to activate the transcription factor Nrf2, which regulates the expression of cytoprotective enzymes such as heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). In this study, a novel semisynthetic flavonoid 7-O-galloylquercetin (or quercetin-7-gallate, 3) was prepared by direct galloylation of quercetin, and its effect on the Nrf2 pathwa...

Increasing epidemiological evidence supports the view that dietary flavonoids have protective roles in oral diseases, including cancer. However, the dietary forms of flavonoids, the flavonoid glycosides, must first be hydrolyzed to the aglycones, which is thought to occur mainly in the intestine. In the present study we tested whether this hydrolytic activity occurs in the oral cavity. Saliva w...

Quercetin is a flavonoid usually found in fruits and vegetables. Aside from its antioxidative effects, quercetin, like other flavonoids, has a various neuropharmacological actions. Quercetin-3-O-rhamnoside (Rham1), quercetin-3-O-rutinoside (Rutin), and quercetin- 3-(2(G)-rhamnosylrutinoside (Rham2) are mono-, di-, and tri-glycosylated forms of quercetin, respectively. In a previous study, we sh...

In this study, the possible involvement of L-type voltage-operated calcium channels in the vasorelaxant effect of the flavonoid quercetin was investigated, using the isolated aortic rings from normal male rats. Addition of quercetin (0.1 µM-1 mM) caused a significant dose-dependent relaxation of noradrenaline (NA)- and KCl-preconstricted rings and nifedipine attenuated this response, especially...

We tested whether the dominant intestinal sugar transporter GLUT2 was inhibited by intestinal luminal compounds that are inefficiently absorbed and naturally present in foods. Because of their abundance in fruits and vegetables, flavonoids were selected as model compounds. Robust inhibition of glucose and fructose transport by GLUT2 expressed in Xenopus laevis oocytes was produced by the flavon...

Although there is strong evidence to suggest that flavonoid consumption is beneficial to human health, the extent to which flavonoids are absorbed and the mechanisms involved are controversial. Contrary to common dogma, we previously demonstrated that quercetin 4'-beta-glucoside, the predominant form of the most abundant dietary flavonoid, quercetin, was not absorbed across Caco-2 cell monolaye...