OBJECTIVE To investigate the possible protection provided by oral quercetin pretreatment against hepatic ischemia-reperfusion injury in rats. METHODS The quercetin (0.13 mmol/kg) was orally administrated in 50 min prior to hepatic ischemia-reperfusion injury. Ascorbic acid was also similarly administered. The hepatic content of quercetin was assayed by high performance liquid chromatography (...

Propolis was used as medicine, cosmetic and beverage additives since past decades. The most important active compounds in the propolis are phenolic and flavonoids, which are in the resin category. The purpose of this study was to measure the total amount of flavonoids and quercetin in propolis of northern Iran and compare obtain data with different extraction methods. The soxhlet, maceration an...

Limited information from human studies indicates that dietary quercetin supplementation influences blood lipid profiles, glycemic response, and inflammatory status, collectively termed cardiometabolic risks. We tested the hypothesis that quercetin-rich supplementation, derived from onion peel extract, improves cardiometabolic risk components in healthy male smokers in a randomized, double blind...

Regular consumption of flavonoids may reduce the risk for CVD. However, the effects of individual flavonoids, for example, quercetin, remain unclear. The present study was undertaken to examine the effects of quercetin supplementation on blood pressure, lipid metabolism, markers of oxidative stress, inflammation, and body composition in an at-risk population of ninety-three overweight or obese ...

Many studies have demonstrated that the flavonoid quercetin protects against cardiovascular disease (CVD) and related risk factors. Atherosclerosis, the underlying cause of CVD, is also attenuated by oral quercetin administration in animal models. Although macrophages are key players during fatty streak formation and plaque progression and aggravation, little is known about the effects of querc...

Quercetin is one of the most widely distributed flavonoids present in fruits and vegetables. The present experiments were performed on rats adapted for 3 wk to a semipurified diet supplemented with 0.2% quercetin. The major part of the circulating metabolites of quercetin (91.5%) are glucurono-sulfo conjugates of isorhamnetin (3'-O-methyl quercetin; 89.1 ± 2.1 μM) and of quercetin (14.7 ± 1.7 μ...

increased serum uric acid is known to be a major risk related to the development of several oxidative stress diseases. the aim of this study was to investigate the effect of parsley, quercetin and kaempferol on serum uric acid levels, liver xanthine oxidoreductase activity and two non-invasive biomarkers of oxidative stress (total antioxidant capacity and malondialdehyde concentration) in norma...

The bioflavonoid quercetin occurs as a range of glycosides in foods, and the composition of these glycosides is species and cultivar specific. In humans, quercetin undergoes extensive phase II biotransformation, resulting in a complex mixture of metabolites. The bioactivity of the individual metabolites depends on the type and position of the conjugates formed during biotransformation. An Agile...

Quercetin is a polyphenol found in food that has numerous health benefits. This study investigated the relationship between quercetin metabolism, gut microbiota composition, and dietary intake in elderly Japanese subjects. A food frequency questionnaire was used to assess dietary intake during the week prior to stool sample collection. Fecal suspensions from 56 subjects were anaerobically incub...

BACKGROUND & AIMS Oxidative stress and low antioxidant levels are implicated in the aetiology of sarcoidosis, an inflammatory disease. Quercetin is a potent dietary antioxidant that also displays anti-inflammatory activities. Consequently, the aim is to examine the effect of quercetin supplementation on markers of oxidative stress and inflammation in sarcoidosis. METHODS A double-blind interv...