30048-34-1Relevant articles and documents
The reduction of oxidation of food products using dioxygenases
Bouwens, Liesbeth C. M.,Bruggeman, Yvonne E.
, p. 562 - 568 (2002)
A novel way of deoxygenating food products by oxygen scavenging enzymes has been developed, especially suitable for food products comprising mono or polyunsaturated fatty acids or both which are very sensitive to oxidation. It has been found that dioxygen
On the difference in decomposition of taxifolin and luteolin vs. fisetin and quercetin in aqueous media
Sokolová, Romana,Rame?ová, ?árka,Kocábová, Jana,Kolivo?ka, Viliam,Degano, Ilaria,Pitzalis, Emanuela
, p. 1375 - 1383 (2016/08/12)
Abstract: The decomposition of flavonols quercetin and fisetin, flavone luteolin and flavanone taxifolin was studied in slightly alkaline solution under ambient conditions. The study was based on spectrophotometry and high-pressure liquid chromatography. Products formed by atmospheric oxygen oxidation and hydrolysis were identified by HPLC–DAD and HPLC–ESI-MS/MS. Only small differences in the chemical structure of flavonoids resulted in extremely variable oxidation pathways and products. Oxidation of flavonols led to the formation of both a benzofuranone derivative and several open structures. On the contrary, the benzofuranone derivative was not found as a product of taxifolin and luteolin oxidative decomposition. These compounds were oxidized to their hydroxylated derivatives and typical open structures. Quercetin was not identified as a possible oxidation product of taxifolin. Graphical Abstract: [Figure not available: see fulltext.]
Identification of the products of oxidation of quercetin by air oxygen at ambient temperature
Zenkevich, Igor G.,Eshchenko, Anna Yu.,Makarova, Svetlana V.,Vitenberg, Alexander G.,Dobryakov, Yuri G.,Utsal, Viktor A.
, p. 654 - 672 (2008/02/01)
Oxidation of quercetin by air oxygen takes place in water and aqueous ethanol solutions under mild conditions, namely in moderately-basic media (pH ～ 8-10) at ambient temperature and in the absence of any radical initiators, without enzymatic catalysis or irradiation of the reaction media by light. The principal reaction products are typical of other oxidative degradation processes of quercetin, namely 3,4-dihydroxy-benzoic (protocatechuic) and 2,4,6-trihydroxybenzoic (phloroglucinic) acids, as well as the decarboxylation product of the latter - 1,3,5-trihydroxybenzene (phloroglucinol). In accordance with the literature data, this process involves the cleavage of the γ-pyrone fragment (ring C) of the quercetin molecule by oxygen, with primary formation of 4,6-dihydroxy-2-(3,4-dihydroxybenzoyloxy)benzoic acid (depside). However under such mild conditions the accepted mechanism of this reaction (oxidative decarbonylation with formation of carbon monoxide, CO) should be reconsidered as preferably an oxidative decarboxylation with formation of carbon dioxide, CO2. Direct head-space analysis of the gaseous components formed during quercetin oxidation in aqueous solution at ambient temperature indicates that the ratio of carbon dioxide/carbon monoxide in the gas phase after acidification of the reaction media is ca. 96:4 %. Oxidation under these mild conditions is typical for other flavonols having OH groups at C3 (e.g., kaempferol), but it is completely suppressed if this hydroxyl group is substituted by a glycoside fragment (as in rutin), or a methyl substituent. An alternative oxidation mechanism involving the direct cleavage of the C2-C3 bond in the diketo-tautomer of quercetin is proposed.
Flavonoid oxidation by the radical generator AIBN: a unified mechanism for quercetin radical scavenging.
Krishnamachari, Venkat,Levine, Lanfang H,Pare, Paul W
, p. 4357 - 4363 (2007/10/03)
Four oxidized flavonoid derivatives generated from reacting quercetin (a pentahydroxylated flavone) with the peroxyl radical generator 2,2'-azobis-isobutyronitrile (AIBN) were isolated by chromatographic methods and identified by NMR and MS analyses. Comp
