title: Flavonoids from italian multifloral honeys reduce the extracellular ferricyanide in human red blood cells.
abstract: In this study we investigated some biological properties of flavonoids recovered in the aqueous (AqE) and ether (EtE) extracts from four Italian multifloral honeys. In particular, a cell-free assay was employed to detect direct reduction of ferricyanide, whereas an assay using intact human erythrocytes was used to measure the ability to donate electrons to a trans-plasma membrane oxidoreductase. It was found that the AqE displays greater "in vitro" ferricyanide-reducing activity than the EtE but, unlike the latter, is virtually ineffective in the cell-based assay. Uptake studies employing high-performance liquid chromatography/mass spectrometry (HPLC/MS) showed that the different results were explained by the inability of AqE components to cross the erythrocyte plasma membrane and by the excellent uptake of EtE flavonoids, which, once within the cell, donate electrons to the membrane oxidoreductase to efficiently reduce extracellular oxidants. The latter property appears to depend on the content of ether-soluble flavonoids in the starting honeys.
authors.affiliation: Istituto di Chimica Biologica Giorgio Fornaini, Via Saffi 2, Università degli Studi di Urbino Carlo Bo, 61029 Urbino (PU), Italy. m.fiorani@uniurb.it
authors.forename: Mara
authors.initials: M
authors.lastname: Fiorani
authors.forename: Augusto
authors.initials: A
authors.lastname: Accorsi
authors.forename: Manuela
authors.initials: M
authors.lastname: Blasa
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Diamantini
authors.forename: Elena
authors.initials: E
authors.lastname: Piatti
mesh_terms: D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000737:chemistry* / Q000187:drug effects; D005292:Ferricyanides / Q000097:blood*; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D035264:Flowers; D006722:Honey / Q000032:analysis*; D007558:Italy; D010084:Oxidation-Reduction
chemical_list: D005292:Ferricyanides; D005419:Flavonoids; C007931:hexacyanoferrate III