Search results for "Quercetin"
showing 10 items of 119 documents
Chronic Administration of Quercetin Induces Biomechanical and Pharmacological Remodeling in the Rat Coronary Arteries
2017
Acute dilation brought about by the dietary flavonoid quercetin in coronary arterioles has been described earlier, but no information is available on its chronic effects. Male Wistar rats (body weight about 190 g) were divided to two groups: the quercetin-treated group (n=22) had quercetin supplementation of approximately 30 mg/kg/day, whereas the control group (n=20) had none. After eight weeks of treatment, intramural coronary arterioles with identical passive diameters (178+/-14 microm and 171+/-9 microm) were prepared and their biomechanics and pharmacological reactivities were tested using pressure arteriography ex vivo. The spontaneous tone of quercetin-treated arteries was higher (16…
Mechanisms involved in the chemoprevention of flavonoids
2001
Flavonoids, widespread in edible plants, have been studied extensively for their anticarcinogenic properties. However, only few studies have been done with these constituents being administered by the dietary route. In our research, the effects of feeding rats with flavone, flavanone, tangeretin, and quercetin were investigated on two steps of aflatoxin B1 (AFB1)-induced hepatocarcinogenesis (initiation and promotion). Nonpolar flavonoids such as flavone, flavanone and tangeretin administered through the initiation period, decreased the number of -gamma-glutamyl transpeptidase-preneoplastic foci. In the same conditions of administration, quercetin, a polyhydroxylated flavonoid, showed no pr…
Differential protective effects of red wine polyphenol extracts (RWEs) on colon carcinogenesis.
2014
Various epidemiological studies have shown that a regular and moderate consumption of red wine is correlated with a decreased relative risk of developing coronary heart disease and cancer. These health benefits are commonly attributed to high contents of polyphenols, particularly resveratrol, representing important sources of antioxidants. However, resveratrol does not seem to be the only bioactive compound present in the wine which contains numerous other polyphenols. The present study investigates the efficiency of red wine extracts (RWEs), containing different polyphenols, on colon cancer cell proliferation in vitro and on colonic aberrant crypt foci (ACF) in vivo. Proliferation, cell cy…
Inhibition of clastogenicity of benzo[a]pyrene and of its trans-7,8-dihydrodiol in mice in vivo by fruits, vegetables, and flavonoids.
2003
In the in vivo mouse bone marrow micronucleus assay, homogenates of spinach, artichoke, peaches, and blue grapes as well as commercial concentrates of these vegetables and fruits reduced induction of micronuclei by benzo[a]pyrene (BaP) by 43-50%. Concentrates of strawberries (31% reduction) and of cauliflower (20% reduction) were less potent. Inhibition of genotoxicity by spinach and peaches was not caused by any delay in maturation of micronucleated erythrocytes as shown by experiments with sampling times of 24, 48, and 72 h after dosing of BaP. Pre-treatment of the mice with spinach 48, 24, and 12h before application of BaP resulted in a 44% reduction of micronuclei while peaches generate…
Chronic quercetin feeding decreases plasma concentrations of salicylamide phase II metabolites in pigs following oral administration.
2011
We investigated acute effects and effects after chronic intake of the orally administered flavonol quercetin on pharmacokinetics of salicylamide metabolites (SAM) after oral administration of salicylamide in pigs. Salicylamide (8 mg/kg body weight) was orally administered to seven pigs either without or with quercetin (10 mg/kg body weight). Additionally, salicylamide was administered to five pigs that had received a diet supplemented with the flavonol for 1 week. Daily quercetin intake was 10 mg/kg in these animals. Co-ingestion of quercetin with the drug did not alter area under the concentration-time curve (AUC(0→∞)), time to achieve maximum plasma concentration (t(max)), mean residence …
Inhibition of ethoxyresorufin deethylase activity by natural flavonoids in human and rat liver microsomes
1990
Several flavones and flavonols (chrysin, quercetin, luteolin, flavone and 7, 8-benzoflavone) were found to inhibit ethoxyresorufin deethylase (EROD) activity in human and rat liver microsomes. In man, molecules without hydroxyl groups are more powerful inhibitors than polyhydroxylated flavonoids (7, 8-benzoflavone greater than flavone greater than chrysin greater than luteolin greater than quercetin greater than morin). In rat, chrysin was the strongest inhibitor and the less effective were morin and 7,8-benzoflavone. For all molecules human microsomes were more sensitive than rat microsomes. The most important difference concerned 7,8-benzoflavone which was 10,000-fold more potent in man.
Effects of a quercetin-rich onion skin extract on 24 h ambulatory blood pressure and endothelial function in overweight-to-obese patients with (pre-)…
2015
AbstractThe polyphenol quercetin may prevent CVD due to its antihypertensive and vasorelaxant properties. We investigated the effects of quercetin after regular intake on blood pressure (BP) in overweight-to-obese patients with pre-hypertension and stage I hypertension. In addition, the potential mechanisms responsible for the hypothesised effect of quercetin on BP were explored. Subjects (n 70) were randomised to receive 162 mg/d quercetin from onion skin extract powder or placebo in a double-blinded, placebo-controlled cross-over trial with 6-week treatment periods separated by a 6-week washout period. Before and after the intervention, ambulatory blood pressure (ABP) and office BP were m…
Antiasthmatic Effects of <i>Galphimia glauca</i>, Gallic Acid, and Related Compounds Prevent Allergen- and Platelet-Activating Factor-Ind…
1992
A methanolic extract from Galphimia glauca (320 mg/kg, orally) inhibited acute bronchial reactions to allergen (ovalbumin, 10 mg/ml) and platelet-activating factor (PAF, 1 microgram/ml) inhalation challenges, but not to histamine or acetylcholine in spontaneously breathing guinea pigs. Furthermore, the PAF-induced bronchial hyperreactivity was markedly reduced. Gallic acid and related compounds as well as the flavonoid, quercetin, were identified as active compounds. Gallic acid, methyl gallate and quercetin showed significant effects after a single oral dose of 45 mg/kg, tetragalloyl quinic acid after 5 mg/kg. Continuous treatment of the animals with one certain fraction (GG II, 3 days, 3 …
Dietary administration of high doses of pterostilbene and quercetin to mice is not toxic.
2009
The aim of this study is to evaluate possible harmful effects of high doses of t-pterostilbene (t-PTER) and quercetin (QUER) in Swiss mice. Mice were fed during 28 days at doses of 0, 30, 300, and 3000 mg/kg body weight/day of t-PTER, QUER, or a mixture of both, t-PTER + QUER, which are equivalent to 5, 50, and 500 times, respectively, the estimated mean human intake of these polyphenols (25 mg/day). Daily oral administration of QUER, t-PTER, or a mixture of both of them did not cause mortality during the experimental period. There were no differences in food and water consumption on sex. No significant body weight gain in the male or female groups was observed. Red blood cell number and th…
Effects of the flavonol quercetin on the bioavailability of simvastatin in pigs
2009
The influence of the dietary flavonol quercetin on the pharmacokinetics of the HMG-CoA reductase inhibitor simvastatin was investigated in pigs. Simvastatin (0.25mg/kg body weight) was orally administered to six pigs either without or with quercetin (10mg/kg). In addition, simvastatin was administered to three pigs that had received a diet supplemented with the flavonol over a period of 1 week. Daily quercetin intake was 10mg/kg in these animals. Co-ingestion of quercetin with the statin did not alter area under the concentration time curve (AUC(0-->infinity)), time to achieve maximum plasma concentration (t(max)) or half-life (t(1/2)) of simvastatin. However, there was a trend towards a re…