Taxonomic group: plant / Streptophyta
(Phylum: Streptophyta)
NCBI PubMed ID: 10938233Publication DOI: 10.1152/ajpregu.2000.279.2.R461Journal NLM ID: 100901230Publisher: Bethesda, MD: American Physiological Society
Correspondence: terao
nutr.med.tokushima-u.ac.jp
Institutions: Department of Nutrition, School of Medicine, The University of Tokushima, Tokushima, Japan, Department of Nursing, School of Medical Sciences, The University of Tokushima, Tokushima, Japan, Kagome Research Institute, Kagome Company, Nishinasuno, Japan
Quercetin is a typical flavonoid present mostly as glycosides in plant foods; it has attracted much attention for its potential beneficial effects in disease prevention. In this study, we examined human volunteers after the short-term ingestion of onion, a vegetable rich in quercetin glucosides. The subjects were served diets containing onion slices (quercetin equivalent: 67.6–93.6 mg/day) with meals for 1 wk. Quercetin was only found in glucuronidase-sulfatase-treated plasma, and its concentration after 10 h of fasting increased from 0.04 ± 0.04 μM before the trial to 0.63 ± 0.72 μM after the 1-wk trial. The quercetin content in low-density lipoprotein (LDL) after glucuronidase-sulfatase treatment corresponded to <1% of the α-tocopherol content. Human LDL isolated from the plasma after the trial showed little improvement of its resistance to copper ion-induced oxidation. It is therefore concluded that conjugated metabolites of quercetin accumulate exclusively in human blood plasma in the concentration range of 0.1 - 1 μM after the short-term ingestion of vegetables rich in quercetin glucosides, although these metabolites are hardly incorporated into plasma LDL.
quercetin metabolites; quercetin glycosides; low-density lipoprotein oxidation; glucuronidation
Structure type: monomer
Location inside paper: p. 463, Results, paragraph 1
Trivial name: isoquercitrin
Compound class: saponin glycoside, glycoside, flavonoid glycoside, flavonol glycoside, flavone glycoside
Contained glycoepitopes: IEDB_142488,IEDB_146664,IEDB_983931,SB_192
Methods: HPLC, enzymatic digestion, LC
Related record ID(s): 66939, 66940
NCBI Taxonomy refs (TaxIDs): 4679Reference(s) to other database(s): CCSD:
49965, CBank-STR:953
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
report error