title: Synthesis and analysis of aminochromes by HPLC-photodiode array. Adrenochrome evaluation in rat blood.
abstract: The catecholamine oxidation process induces cardiotoxicity and neurotoxicity. Catecholamines can oxidize to aminochromes through autoxidation or by enzymatic or non-enzymatic catalysis. Although some toxic effects seem to be related to the formation of aminochromes there is still scarce information concerning the identification and evaluation of these compounds in in vivo models. In this study five catecholamines were oxidized to their respective aminochromes: adrenaline/adrenochrome; noradrenaline/noradrenochrome; dopa/dopachrome; dopamine/dopaminochrome; and isoproterenol/isoprenochrome. The evaluation of the catecholamines oxidation profile was performed by HPLC with photodiode array detection and using either enzymatic (tyrosinase) or non-enzymatic [Ag(2)O, CuSO(4), NaIO(4) and K(3)Fe(CN)(6)] catalytic systems. The NaIO(4) was found to be the most efficient oxidant of catecholamines. An isocratic reverse-phase HPLC method was developed to analyse each pair of catecholamine-aminochrome. The analytical system was then applied to the detection of adrenochrome in rat blood at 490 nm. Thus, adrenochrome was administered i.p. to rats and its concentration in whole blood was monitored after 5, 15 and 25 min. Blood treatment for adrenochrome evaluation consists of an acidification for protein precipitation followed by a rapid neutralization. The results showed a rapid decrease of adrenochrome concentration in blood after its administration. The adrenochrome present in blood was characterized by UV and tandem mass spectrometry.
authors.affiliation: CEQUP/Serviço de Toxicologia, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4050-047 Porto, Portugal. remiao@ff.up.pt
authors.forename: Fernando
authors.initials: F
authors.lastname: Remião
authors.forename: Nuno
authors.initials: N
authors.lastname: Milhazes
authors.forename: Fernanda
authors.initials: F
authors.lastname: Borges
authors.forename: Félix
authors.initials: F
authors.lastname: Carvalho
authors.forename: Maria L
authors.initials: ML
authors.lastname: Bastos
authors.forename: Francisco
authors.initials: F
authors.lastname: Lemos-Amado
authors.forename: Pedro
authors.initials: P
authors.lastname: Domingues
authors.forename: A
authors.initials: A
authors.lastname: Ferrer-Correia
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D045563:Indolequinones; D007211:Indoles / Q000097:blood* / Q000138:chemical synthesis*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D045563:Indolequinones; D007211:Indoles; C091584:aminochrome 1