30048-34-1

Upstream product

• 36535-79-2 quercetin-3-O-β-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside 
• 67-56-1 methanol 
• 117-39-5 quercetol 
• 64-17-5 ethanol 
• 480-18-2 taxifolin 
• 491-70-3 2-(3,4-Dihydroxy-phenyl)-5,7-dihydroxy-chromen-4-on 
• 882427-70-5 benzyl 2,4-bis(benzyloxy)-6-hydroxybenzoate 
• 882427-73-8 2,4-Bis-benzyloxy-6-(3,4-bis-benzyloxy-benzoyloxy)-benzoic acid benzyl ester 

Downstream Products

• 25982-03-0 methyl 4,6-dimethoxy-2-(3,4-dimethoxybenzoyloxy)-salicylate 

Relevant academic research and scientific papers

The reduction of oxidation of food products using dioxygenases

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

Superoxide anion radical-induced dioxygenolysis of quercetin as a mimic of quercetinase

Reaction of quercetin with superoxide anion radical is triggered by proton abstraction from quercetin to yield dismutated products of superoxide and deprotonated quercetin, which allows quercetinase-like dioxygenation to give the corresponding depside in

On the difference in decomposition of taxifolin and luteolin vs. fisetin and quercetin in aqueous media

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.]

The influence of the host-guest interaction on the oxidation of natural flavonoid dyes

The influence of the molecular cavity protection on degradation processes of bioorganic compounds quercetin and luteolin used as the original dyes in old tapestries was studied. The degradation processes were studied by electrochemical methods in aqueous media. The products of the exhaustive electrolysis were separated and identified by GC-MS analysis. Cyclic voltammetry characteristics indicate that the inclusion complex is formed. The inclusion affects the redox potentials of both oxidation waves related to the different dissociation forms of the flavonoid molecule. It was shown that decomposition products formed by the oxidation of quercetin are stabilized in the cavity of β-cyclodextrin, including the main oxidation product 2(3',4'- dihydroxybenzoyl)-2,4,6-trihydroxybenzofuran-3(2H)-one. The formation of the 1:1 inclusion complex of luteolin with β-cyclodextrin is supported by the enhancement of fluorescence intensity. In the case of quercetin, a decrease of fluorescence intensity occurs when 1:1 inclusion complex with β-cyclodextrin is formed.

Identification of the products of oxidation of quercetin by air oxygen at ambient temperature

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.

First chemical synthesis of three natural depsides involved in flavonol catabolism and related to quercetinase catalysis

We report here the first chemical synthesis of three depsides related to quercetinase-catalyzed degradation of kaempferol, quercetin, and myricetin. The three depsides were constructed through the coupling of suitably protected phloroglucinol carboxylic acid and hydroxy-perbenzylated, derivatives of gallic, protocatechuic, and 4-hydroxy benzoic acids. The three synthesized target compounds proved to be identical to their natural counterparts, arising from quercetinase action on corresponding flavonols. Copyright Taylor & Francis Group, LLC.

Flavonoid oxidation by the radical generator AIBN: a unified mechanism for quercetin radical scavenging.

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

MECHANISM OF QUERCETIN OXYGENATION A POSSIBLE MODEL FOR HAEM DEGRADATION

Quercetin undergoes base-catalysed oxidative decarbonylation by a mechanism involving only one oxygen molecule, unlike the apperently similar step in haem catabolism, which requires two oxygen molecules.