This is the first in vitro study to investigate gender-related differences in the regulation of human cytochrome P450 by the flavonoids. Activities of CYP2E1 and CYP3A were measured in the presence of quercetin, myricetin, or isorhamnetin in hepatic microsomal pools from male and female donors. Hydroxylation of p-nitrophenol (PNPH) was measured to determine CYP2E1 activity, and O-dealkylation of 7-benzyloxy-4-trifluoromethylcoumarin (BFC) was measured to determine CYP3A activity. Quercetin, but not myricetin or isorhamnetin, competitively inhibited PNPH activity in human recombinant cDNA-expressed CYP2E1 with the Ki=52.1±6.31μM. In the human microsomes, slight inhibition of PNPH activity by quercetin was not considered as physiologically relevant. Quercetin inhibited BFC activity in human recombinant cDNA-expressed CYP3A4 competitively with the Ki=15.4±1.52μM, and myricetin - noncompetitively with the Ki=74.6±7.99μM. The degree of inhibition by quercetin was similar between genders. Myricetin showed somewhat stronger inhibition in female pools, but the Ki values were higher than physiologically relevant concentrations. Isorhamnetin did not affect either PNPH or BFC activity. We concluded that observed inhibition of CYP2E1 and CYP3A by some flavonols were not gender-dependent.

• Klíčová slova
• Cytochrome P450, Females, Flavonols, Hepatic microsomes, Males, isorhamnetin (PubChem CID: 5281654), myricetin (PubChem CID: 5281672), quercetin (PubChem CID: 5280343),
• MeSH
• cytochrom P-450 CYP2E1 metabolismus   MeSH
• cytochrom P-450 CYP3A metabolismus   MeSH
• flavonoidy farmakologie   MeSH
• hydroxylace MeSH
• inhibitory cytochromu P450 CYP2E1 farmakologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• jaterní mikrozomy účinky léků   metabolismus   MeSH
• kumariny metabolismus   MeSH
• lidé MeSH
• nitrofenoly metabolismus   MeSH
• quercetin analogy a deriváty   farmakologie   MeSH
• sexuální faktory MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3-methylquercetin MeSH Prohlížeč
• 4-nitrophenol MeSH Prohlížeč
• 7-benzyloxy-4-trifluoromethylcoumarin MeSH Prohlížeč
• cytochrom P-450 CYP2E1 MeSH
• cytochrom P-450 CYP3A MeSH
• flavonoidy MeSH
• inhibitory cytochromu P450 CYP2E1 MeSH
• inhibitory enzymů MeSH
• kumariny MeSH
• myricetin MeSH Prohlížeč
• nitrofenoly MeSH
• quercetin MeSH

This study investigated the effects of the addition of onion waste fractions into gluten-free (GF) bread to promote its health benefits. 5% of the control (C) GF flour blend was replaced with three waste fractions in the form of: fried onion (FO), dried onion (DO) and onion peel (OP). Antioxidant activity, content of flavonols and total polyphenols of breads increased in the following order: C < FO < DO < OP. No differences were observed in sensory analysis. We found that quercetin glycosides, dimers and trimer in OP-bread, determined according to their mass spectra, decomposed during baking and released free quercetin, which points to their thermal instability. Cross-over study revealed that consumption of OP-bread significantly increased (p < 0.05) antioxidant activity of consumers' blood compared to control bread consumption, indicating good bioavailability of flavonols. Results suggest incorporation of OP into GF bread can increase its biological value with satisfactory sensory acceptance.

• Klíčová slova
• Flavonoids, Gluten-free bread, HPLC–MS/MS, Onion waste, Quercetin (PubChem CID 5280343), Quercetin dimers, Quercetin trimers, Quercetin-3,4′-O-diglucoside (PubChem CID 44259154), Quercetin-4′-O-glucoside (PubChem CID 12442954), Rutin (PubChem CID 5280805), Thermal processing,
• MeSH
• biologická dostupnost MeSH
• česneky chemie   metabolismus   MeSH
• chléb analýza   MeSH
• klinické křížové studie MeSH
• polyfenoly chemie   metabolismus   MeSH
• quercetin chemie   metabolismus   MeSH
• rutin chemie   metabolismus   MeSH
• vaření MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• polyfenoly MeSH
• quercetin MeSH
• rutin MeSH

Tartary buckwheat achenes are rich in rutin. However, its utilisation as a food is low due to the bitter taste of the products because of the transformation of rutin to quercetin. The aim of this study was to determine the stability of rutin and selected flavonoids, which are influenced by the different sample preparations exposing the achenes to higher temperatures (60 °C, 100 °C, and 140 °C), and also to determine the specificity of the rutin degrading enzymes in Tartary buckwheat. The achenes were directly extracted with methanol pre-extracted with hexane, or lyophilised before extraction. The rutin and quercetin contents were determined by HPLC. The rutin-degrading enzymes in Tartary buckwheat achenes were not inactivated after a heat treatment up to 140 °C acting on them for three hours; neither to lyophilisation nor pre-extraction with hexane. The rutin-degrading enzymes probably caused the deglycosylation of kaempferol-3-O-rutinoside, kaempferol-3-O-β-d-glucoside and piceid. Rutin-degrading enzymes were inactivated with 100% methanol.

• Klíčová slova
• Hexane, Kaempferol-3-O-rutinoside (PubChem CID: 24211973), Kaempferol-3-O-β-d-glucoside (PubChem CID: 528210), Lyophilisation, Methanol, Protocatechuic acid (PubChem CID: 72), Quercetin, Quercetin (PubChem CID: 5280343), Rutin (PubChem CID: 5280805), Rutin-degrading enzyme, Temperature, trans-Piceid (PubChem CID: 5281718),
• MeSH
• chemická frakcionace MeSH
• Fagopyrum chemie   MeSH
• flavonoidy chemie   metabolismus   MeSH
• glukosidy metabolismus   MeSH
• glykosylace MeSH
• kempferoly metabolismus   MeSH
• lyofilizace MeSH
• quercetin analýza   metabolismus   MeSH
• rutin analýza   chemie   metabolismus   MeSH
• semena rostlinná chemie   MeSH
• stilbeny metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• flavonoidy MeSH
• glukosidy MeSH
• kaempferol-3-O-rutinoside MeSH Prohlížeč
• kempferoly MeSH
• polydatin MeSH Prohlížeč
• quercetin MeSH
• rutin MeSH
• stilbeny MeSH

Berries of four gooseberry (Ribes uva-crispa L.) cultivars of Invicta, Rixanta, Karat and Black Negus and five currant (Ribes L.) cultivars of NS 11, Focus, Ben Gairn, Otelo and Viola were evaluated as potential sources of bioactive compounds with extraordinary antioxidant activity. Their total phenolic, flavonoid and anthocyanin contents were determined in the range of 3.52-30.77 g GA.kg-1, 2.83-17.35 g RE.kg-1 and 0.03-186.12 mg COG.100 g-1, respectively. Furthermore, quantification of phenolic compounds and vitamins was established by high-performance liquid chromatography-diode array detection. Flavonoids were the most abundant phenolic substances in the range of 345.0-3726.5 mg.kg-1. Ascorbic acid and vitamin E were established in the amounts of 6.2-14.04 g.kg-1 and 0.43-12.85 mg.kg-1, respectively. Considering all analyzed factors and antioxidant activities determined by various methods (DPPH, ACW and ACL), red gooseberry Black Negus and black currant Otelo were the most significant cultivars.

• Klíčová slova
• Antioxidant activity, Ascorbic acid, Ascorbic acid (PubChem CID: 54670067), Chlorogenic acid (PubChem CID: 1794427), Currant, Cyanidin-3-o-glucoside (PubChem CID: 12303203), DPPH (PubChem CID: 2735032), Epigallocatechin (PubChem CID: 72277), Gallic acid (PubChem CID: 370), Gooseberry, HPLC, Pearson correlation coefficient, Phenolic compounds, Protocatechuic (3,4-Dihydroxybenzoic) acid (PubChem CID: 72), Quercetin (PubChem CID: 5280343), Rutin (PubChem CID: 5280805), Trolox (PubChem CID: 40634), Vitamin E,
• MeSH
• anthokyaniny analýza   MeSH
• antioxidancia chemie   MeSH
• fenoly analýza   MeSH
• flavonoidy analýza   MeSH
• kyselina askorbová analýza   MeSH
• ovoce chemie   metabolismus   MeSH
• Ribes chemie   metabolismus   MeSH
• vitamin E analýza   MeSH
• vysokoúčinná kapalinová chromatografie * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anthokyaniny MeSH
• antioxidancia MeSH
• fenoly MeSH
• flavonoidy MeSH
• kyselina askorbová MeSH
• vitamin E MeSH