title: Effect of quercetin and its glucuronide metabolite upon 6-hydroxydopamine-induced oxidative damage in Neuro-2a cells.
abstract: Quercetin is ubiquitously distributed in plant foods. This antioxidative polyphenol is mostly converted to conjugated metabolites in the body. Parkinson disease (PD) has been suggested to be related to oxidative stress derived from abnormal dopaminergic activity. We evaluated if dietary quercetin contributes to the antioxidant network in the central nervous system from the viewpoint of PD prevention. A neurotoxin, 6-hydroxydopamine (6-OHDA), was used as a model of PD. 6-OHDA-induced H₂O₂ production and cell death in mouse neuroblastoma, Neuro-2a. Quercetin aglycone suppressed 6-OHDA-induced H₂O₂ production and cell death, although aglycone itself reduced cell viability at higher concentration. Quercetin 3-O-β-D-glucuronide (Q3GA), which is an antioxidative metabolite of dietary quercetin, was little incorporated into the cell resulting in neither suppression of 6-OHDA-induced cell death nor reduction of cell viability. Q3GA was found to be deconjugated to quercetin by microglial MG-6 cells. These results indicate that quercetin metabolites should be converted to their aglycone to exert preventive effect on damage to neuronal cells.
authors.affiliation: Department of Food Science, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Mukai
authors.forename: Kyuichi
authors.initials: K
authors.lastname: Kawabata
authors.forename: Seiko
authors.initials: S
authors.lastname: Otsuka
authors.forename: Akari
authors.initials: A
authors.lastname: Ishisaka
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Kawai
authors.forename: Zai-Si
authors.initials: ZS
authors.lastname: Ji
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuboi
authors.forename: Junji
authors.initials: J
authors.lastname: Terao
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001692:Biological Transport; D016923:Cell Death; D045744:Cell Line, Tumor; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D016627:Oxidopamine / Q000494:pharmacology*; D011794:Quercetin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000975:Antioxidants; C443401:quercetin 3-O-glucuronide; D016627:Oxidopamine; D011794:Quercetin; D006861:Hydrogen Peroxide