The effects of several naturally occurring and synthetic flavonoids on the metabolism of benzo(a)pyrene and aflatoxin B1 were evaluated. Addition of apigenin, chrysin, fisetin, flavonone, galangin, hesperitin, kaempferol, morin, myricetin, haringenin, or quercetin to human liver microsomes inhibited the hydroxylation of benzo(a)pyrene. In contrast to these results, the addition of flavone, nobi...

The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 ̊C have been studied. The following flavonoids; quercetin, rutin and morin significantly protected erythrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by ...

The seeds of Indigofera heterantha yielded a flavonoid characterized as quercetin 3-O-α-L-rhamnoside along with known 3,5,7-trihydroxy-6,4 ́-dimethoxyflavone and 3,5,4 ́-trihydroxy-6,7-dimethoxyflavone. The isolated compounds were characterized by using modern spectroscopic techniques such as UV, IR, NMR and mass.

Flavonoids are a class of polyphenolic compounds present in fruits and vegetables. Several studies have demonstrated a relationship between the consumption of flavonoid-rich diets and the prevention of human diseases including neurodegenerative disorders. Thus, we assessed the effect of quercetin (3,3',4',5,7-pentahydroxyflavone) on oxidative stress and memory retrieval using a step-through pas...

Obesity-induced hypothalamic inflammation is characterized by activation of microglia, which are resident macrophages of the central nervous system, and is implicated in the derangement of energy homeostasis, metabolic complications, and neurodegenerative diseases. Quercetin, a naturally occurring flavonoid, is known to protect against oxidative stress and inflammation-related metabolic complic...

Evidence has accumulated that dietary polyphenols, in particular, flavonoids, have protective effects against oral cancer. In this study, we have examined the effects of quercetin, a major dietary flavonoid, on cell growth and necrosis/apoptosis and cell cycle regulation in human oral squamous carcinoma SCC-9 cells. Quercetin induced dose- and time-dependent, irreversible inhibition of cell gro...

Four hitherto undescribed Clostridium strains capable of cleaving the C ring of quercetin, kaempferol, and naringenin at C-3-C-4 were isolated from the fecal flora of humans. None of the strains cleaved catechin. C-ring fission occurred when the substrate was either in solution or in suspension. Mixed cultures of flavonoid-hydrolyzing bacteria, flavonoid-cleaving bacteria, and Escherichia coli,...

Hydroxycinnamic acids and flavonoids are dietary phenolic antioxidants that are abundant in our diet. Hydroxycinnamic acids are highly sulfated in vivo, and sulfotransferases (SULTs), in particular SULT1A1, play a major role in their metabolism. Flavonoids are potent inhibitors of human SULTs. In this study, the potential metabolic interaction between dietary hydroxycinnamic acids and flavonoid...

Studies have suggested that dietary flavonoids are helpful in the prevention of atherosclerosis and cardiovascular disease. Antioxidant activity should be noted as underlying mechanism of their health impact in the vascular system, as atherosclerosis is closely related to oxidative events such as oxidized LDL accumulation in the macrophages. Vegetables contain a variety of flavonoids, such as f...

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 ...