The title salt, C(14)H(31)N(2) (+)·C(15)H(9)O(7) (-), was obtained in the reaction of quercetin with n-butyl-amine in a mixture of acetone and hexane. The crystal structure determination shows that the quercetin donates one of its phenol H atoms to the N-butyl-4-butyl-imino-2-methyl-pentan-2-amine mol-ecule. The crystal structure of the salt is stabilized by intramolecular (N-H⋯N for the cation...

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...

Three flavonol triglycosides kaempferol 3-[2Gal-(4-acetylrhamnosyl)robinobioside], kaempferol 3-(2Gal-rhamnosylrobinobioside) and quercetin 3-(2G-rhamnosylrutinoside) have been isolated from a methanolic extract of Galega officinalis aerial parts. They are reported for the first time in the genus Galega; moreover, the acetylated triglycoside is a new natural product.

Nine flavonoids were isolated and characterized from the leaves of Zanthoxylum bungeanum. Their structures were elucidated by spectroscopic techniques as quercetin (1), afzelin (2), quercitrin (3), trifolin (4), quercetin-3-O-β-D-glucoside (5), isorhamnetin 3-O-α-L-rhamnoside (6), hyperoside (7), vitexin (8) and rutin (9). All compounds were isolated from the leaves of Z. bungeanum for the firs...

Although the flavonol quercetin is used as a supplement in commercial dog food, data on quercetin bioavailability in dogs are not available. Thus, we investigated quercetin bioavailability (measured as area under the concentration-time curve) in nine adult beagle dogs at an oral dose of 10 mg/kg body weight (b.w.). The major fraction (>80 %) of flavonols circulating in blood plasma were conjuga...

It was evaluated the inhibitory action of quercetin-3-O-beta-D-glucuronopyranoside (QGC) on reflux esophagitis and gastritis in rats. QGC was isolated from the herba of Rumex Aquaticus. Reflux esophagitis or gastritis was induced surgically or by administering indomethacin, respectively. Oral QGC decreased ulcer index, injury area, gastric volume, and acid output and increased gastric pH as com...

From the leaves of Aquilaria sinensis (LOUR.) GILG, a novel benzophenone glucoside, designated as aquilarinoside A (1), and a new flavonoid, as 7-beta-D-glucoside of 5-O-methylapigenin (2), along with eight known compounds (3-10) were isolated. The structures of 1 and 2 were fully characterized by spectroscopic methods (1D, 2D NMR and MS) and the relative stereochemistry was assigned based on n...

Cigarette smoking is known to aggravate Graves' orbitopathy (GO) severity by enhancing adipogenesis. We investigated the effect of quercetin, an antioxidant, on adipocyte differentiation induced by cigarette smoke extract (CSE) in primary cultured orbital fibroblasts (OFs) from GO patients. Freshly prepared CSE was added to the cells and H(2)O(2) was used as a positive control. Intracellular re...