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 ...

Three new glycosides: thotneoside A (quercetin 3-O-(6″-O-phenylacetyl)-β-D-galactopyranoside) (1), thotneoside B (quercetin 3-O-(6″-O-phenylacetyl)-β-D-glucopyranoside) (2) and thotneoside C (3-methyl-2-butenoic acid 1-O-β-D-glucopyranoside) (3), together with nine known compounds; quercetin (4), quercetin 3-O-β-D-galactopyranoside (5), quercetin 3-O-(6″-O-galloyl)-β-D-galactopyranoside (6), qu...

Oxidized low-density lipoprotein contributes to atherosclerotic plaque formation, and quercetin is expected to exert anti-atherosclerotic effects. We previously reported accumulation of conjugated quercetin metabolites in the aorta of rabbits fed high-cholesterol diets with quercetin glucosides, resulting in attenuation of lipid peroxidation and inhibition of lipid accumulation. Caveolin-1, a m...

Our previous studies have shown that quercetin inhibits Cox-2 and Bcl-2 expressions, and induces human leukemia HL-60 cell apoptosis. In order to investigate the role of AMP-activated protein kinase (AMPK) on quercetin-induced apoptosis of HL-60 cells, we used flow cytometry to detect cell apoptosis. The expressions of LKB1, phosphorylated AMPK (p-AMPK), and Cox-2 protein were detected in HL-60...

The effects of dietary supplementation of flavonol quercetin on both 7,12-dimethylbenz(a)anthracene (DMBA)- and N-nitrosomethylurea-induced mammary cancer in female Sprague-Dawley rats were determined. Quercetin diet was started 1 wk before intragastric instillation of DMBA (65 mg/kg of body weight) or i.v. injection of N-nitrosomethylurea (50 mg/kg of body weight) and was continued during the ...

BACKGROUND Acute respiratory distress syndrome (ARDS) can result in a life-threatening form of respiratory failure, and established, effective pharmacotherapies are therefore urgently required. Quercetin is one of the most common flavonoids found in fruits and vegetables, and has potent anti-inflammatory and anti-oxidant activities. Quercetin has been demonstrated to exhibit cytoprotective effe...

The accumulation of cholesterol in macrophages could induce the formation of foam cells and increase the risk of developing atherosclerosis. We wonder if quercetin, one of flavonoids with anti-inflammation functions in different cell types, could elevate the development of foam cells formation in atherosclerosis. We treated foam cells derived from oxLDL induced THP-1 cells with quercetin, and e...

Quercetin inhibits proliferation of human gastric and colonic cancer cells in vitro by suppressing mitosis and increasing apoptosis. Quercetin might therefore act as an anticarcinogen in the alimentary tract, but previous findings have been inconsistent. We fed rats quercetin at dietary concentrations of 1, 5, 20, and 50 g/kg. At < or = 20 g/kg, we observed a statistically significant reduction...

Quercetin is a major dietary flavonoid found in onions and other vegetables. It is known that dietary quercetin is metabolized in the intestinal mucosa and the liver and is present as its glucuronide/sulfate conjugates with or without methylation. Although quercetin is known to possess strong antioxidant activity, there are only limited reports on the antioxidant activity of its metabolites. In...