title: Evaluation of the inhibitory effects of quercetin-related flavonoids and tea catechins on the monoamine oxidase-A reaction in mouse brain mitochondria.
abstract: Quercetin, a typical dietary flavonoid, is thought to exert antidepressant effects by inhibiting the monoamine oxidase-A (MAO-A) reaction, which is responsible for regulation of the metabolism of the neurotransmitter 5-hydroxytryptamine (5-HT) in the brain. This study compared the MAO-A inhibitory activity of quercetin with those of O-methylated quercetin (isorhamnetin, tamarixetin), luteolin, and green tea catechins ((-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-epigallocatechin gallate) by measuring the formation of the oxidative deamination product of 5-HT, 5-hydroxyindole aldehyde (5-HIAL), in mouse brain mitochondria. Quercetin was inferior to luteolin in the inhibition of MAO-A activity, whereas isorhamnetin, tamarixetin, and tea catechins scarcely exerted inhibitory activity. Quercetin did not affect MAO-A activity in mouse intestinal mitochondria, indicating that it does not evoke side effects on the metabolism of dietary monoamines in the gut. These data suggest that quercetin is a weak (but safe) MAO-A inhibitor in the modulation of 5-HT levels in the brain.
authors.affiliation: Department of Food Sciences, University of Tokushima Graduate School, Tokushima, Japan.
authors.forename: Yauhen
authors.initials: Y
authors.lastname: Bandaruk
authors.forename: Rie
authors.initials: R
authors.lastname: Mukai
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kawamura
authors.forename: Hisao
authors.initials: H
authors.lastname: Nemoto
authors.forename: Junji
authors.initials: J
authors.lastname: Terao
mesh_terms: D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D002392:Catechin / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007421:Intestine, Small / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000201:enzymology*; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D011794:Quercetin / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D013662:Tea / Q000737:chemistry
chemical_list: D005419:Flavonoids; D008996:Monoamine Oxidase Inhibitors; D011994:Recombinant Proteins; D013662:Tea; D002392:Catechin; D011794:Quercetin; D008995:Monoamine Oxidase