19254-30-9

Upstream product

• 40554-95-8 3,7-bis(benzyloxy)-2-{4-(benzyloxy)-3-(β-D-glucopyranosyloxy)phenyl}-5-hydroxy-4H-1-benzopyran-4-one 
• 572-09-8 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide 
• 1021297-98-2 quercetin 5,3'-di-O-β-D-glucopyranoside 
• 1239884-38-8 quercetin-3'-O-tetra-O-acetyl-β-D-glucopyranoside 
• 357194-12-8 3,7-bisbenzyloxy-2-(3-(2,3,4,6-tetra-O-acetyl)-β-D-glucopyranosyloxy-4-benzyloxyphenyl)-5-hydroxyl-4H-chromen-4-one 
• 1313191-80-8 2-(3-(2,3,4,6-tetra-O-acetyl)-β-D-glucopyranosyloxy-4-benzyloxyphenyl)-3,5,7-tribenzyloxy-4H-chromen-4-one 
• 1313191-81-9 2-(3-β-D-glucopyranosyloxy-4-benzyloxyphenyl)-3,5,7-tribenzyloxy-4H-chromen-4-one 
• 117-39-5 quercetol 
• 133-89-1 UDP-glucose 

Downstream Products

• 102031-21-0 2-(3-β-D-glucopyranosyloxy-4-methoxy-phenyl)-3,5,7-trimethoxy-chromen-4-one 
• 117-39-5 quercetol 

Relevant academic research and scientific papers

Regioselective formation of quercetin 5-O-glucoside from orally administered quercetin in the silkworm, Bombyx mori

The cocoons of some races of the silkworm, Bombyx mori, have been shown to contain 5-O-glucosylated flavonoids, which do not occur naturally in the leaves of their host plant, mulberry (Morus alba). Thus, dietary flavonoids could be biotransformed in this insect. In this study, we found that after feeding silkworms a diet rich in the flavonol quercetin, quercetin 5-O-glucoside was the predominant metabolite in the midgut tissue, while quercetin 5,4′-di-O-glucoside was the major constituent in the hemolymph and silk glands. UDP-glucosyltransferase (UGT) in the midgut could transfer glucose to each of the hydroxyl groups of quercetin, with a preference for formation of 5-O-glucoside, while quercetin 5,4′-di-O-glucoside was predominantly produced if the enzyme extracts of either the fat body or silk glands were incubated with quercetin 5-O-glucoside and UDP-glucose. These results suggest that dietary quercetin was glucosylated at the 5-O position in the midgut as the first-pass metabolite of quercetin after oral absorption, then glucosylated at the 4′-O position in the fat body or silk glands. The 5-O-glucosylated flavonoids retained biological activity in the insect, since the total free radical scavenging capacity of several tissues increased after oral administration of quercetin.

Regiospecific synthesis of quercetin O-β-d-glucosylated and O-β-d-glucuronidated isomers

Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide.

Who is the king? The α-hydroxy-β-oxo-α,β-enone moiety or the catechol b ring: Relationship between the structure of quercetin derivatives and their pro-oxidative abilities

Quercetin and other flavonoids have been reported to exhibit both antioxidant and pro-oxidant properties. Most studies about the pro-oxidative ability were conducted in the presence of metal ions, and the essential functional moiety of quercetin responsib

Cloning and functional characterisation of two regioselective flavonoid glucosyltransferases from Beta vulgaris

Two full-length cDNAs encoding flavonoid-specific glucosyltransferases, UGT73A4 and UGT71F1, were isolated from a cDNA library of Beta vulgaris (Amaranthaceae) cell suspension cultures. They displayed high identity to position-specific betanidin and flavonoid glucosyltransferases from Dorotheanthus bellidiformis (Aizoaceae) and to enzymes with similar substrate specificities from various plant families. The open reading frame of the sequences encode proteins of 476 (UGT73A4) and 492 (UGT71F1) amino acids with calculated molecular masses of 54.07 kDa and 54.39 kDa, and isoelectric points of 5.8 and 5.6, respectively. Both enzymes were functionally expressed in Escherichia coli as His- and GST-tagged proteins, respectively. They exhibited a broad substrate specificity, but a distinct regioselectivity, glucosylating a variety of flavonols, flavones, flavanones, and coumarins. UGT73A4 showed a preference for the 4′- and 7-OH position in the flavonoids, whereas UGT71F1 preferentially glucosylated the 3- or the 7-OH position. Glucosylation of betanidin, the aglycone of the major betacyanin, betanin, in B. vulgaris was also observed to a low extent by both enzymes. Several O-glycosylated vitexin derivatives isolated from leaves of young B. vulgaris plants and rutin obtained from B. vulgaris tissue culture are discussed as potential endogenous products of UGT73A4 and UGT71F1. The results are analyzed with regard to evolution and specificity of plant natural product glucosyltransferases.

Quercetin (=2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one) Glycosides and Sulfates: Chemical Synthesis, Complexation, and Antioxidant Properties

Glycosides, acylated glycosides, and sulfates of Quercetin (=3,3',4',5,7-pentahydroxyflavone; 1), which is, together with its derivatives, among the most common polyophenols found in plants and in the human diet, were prepared and quantitatively investiga