A high-throughput method for the extraction and analysis of quercetin in human plasma using 96-well SPE and LC-(ESI)MS/MS (7 min/run) is described. Quercetin exists as a range of glycosides in foods. The dominant types of quercetin glycosides vary depending on genetics (i.e., species and cultivar). Dietary sources include onions and apples (i.e., the peel). Herein the quercetin glycoside compos...

BACKGROUND Leishmaniasis, a parasitic disease caused by protozoa of the genus Leishmania, affects more than 12 million people worldwide. Quercetin has generated considerable interest as a pharmaceutical compound with a wide range of therapeutic activities. One such activity is exhibited against the bloodstream parasite Trypanosoma brucei and amastigotes of Leishmania donovani. However, the mech...

Diets high in quercetin may decrease the risk of developing cardiovascular disease. We tested whether quercetin delays or reduces the severity of hypertension, vascular dysfunction, or cardiac hypertrophy in the spontaneously hypertensive rat (SHR). Normotensive, 5-wk-old SHR consumed standard (n = 18) or quercetin-supplemented diet (1.5 g quercetin/kg diet, n = 22, SHR-Q) for 5 or 11 wk. Wista...

Studies have shown that the 26S proteasome is involved in cell cycle control, transcription, DNA repair, immune response and protein synthesis. In the present study, we investigated the antiproliferative effects of the proteasome inhibitor bortezomib and heat shock protein (Hsp)70 inhibitors on the B16F10 melanoma cell line. The IC50 value of bortezomib was found to be 2.46 nM, while that of th...

BACKGROUND PCOS is a leading endocrinopathy of young women instigating androgens elevation, insulin resistance, obesity, cardiometabolic and menstrual complications. The study investigated the effects of quercetin in a letrozole induced rat model of polycystic ovarian syndrome, which displayed both clinical and metabolic features as in PCOS women. METHODS Female Sprague Dawley (SD) rats were ...

The protective action of quercetin against the pro-oxidant and apoptotic effect of etoposide was investigated in HL-60 cells with a high level of myeloperoxidase (MPO) activity and in cells treated with MPO inhibitor, 4-aminobenzoic acid hydrazide (ABAH). Quercetin significantly protected MPO-rich cells against the pro-oxidative (p<0.05) and apoptotic (p<0.05) effects of etoposide. Pre-treatmen...

The autooxidation of quercetin under laboratory conditions was studied by changes of the absorption spectra during seven hours after dilution. The influence of the primal solvent was observed. In case of quercetin dissolved in ethanol, there can be observed the decrease in λmax at 380 nm, in case of quercetin dissolved in methanol; there can be observed the decrease in λmax at 385 nm, in case o...

We report a study of nanoribbons of quercetin, a phase I clinical trial anticancer drug, and their inhibitory effects on cancer cell proliferation. Novel quercetin nanoribbons have been prepared by atmospheric pressure physical vapor deposition (PVD). The nanostructures have been characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, and Raman spect...

Investigation of the aerial parts of the medicinal plant Hypericum laricifolium led to the isolation of two new natural products, hentriacontanyl caffeate (1a), nonacosanyl caffeate (1b). In addition, stigmasterol, beta-sitosterol, 3-epi-betulinic acid (2), caffeic acid (3), ferulic acid, docosanol, p-hydroxybenzoic acid, 3,4-dimethoxy benzoic acid, quercetin (4), quercetin-3-O-galactoside (5),...

Nine flavonoid compounds: kaempferol 3-0-beta-(6"-p-coumaroyl)-glucopyranoside, myricetin 3-O-beta-glucopyranoside, quercetin 3-0-beta-glucopyranoside, quercetin 3-0-alpha-rhamnopyranosyl (1-->6)-beta-glucopyranoside, kaempferol 3-0-beta-glucopyranoside, kaempferol 3-0-alpha-rhamnopyranosyl (1-->6)-beta-glucopyranoside, quercetin 7-0-beta-glucoside, quercetin 7-0-beta-diglucoside, kaempferol 7-...