Synthesis and analysis of aminochromes by HPLC-photodiode array. Adrenochrome evaluation in rat blood.
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.
Remião
Fernando
F
CEQUP/Serviço de Toxicologia, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4050-047 Porto, Portugal. remiao@ff.up.pt
Milhazes
Nuno
N
Borges
Fernanda
F
Carvalho
Félix
F
Bastos
Maria L
ML
Lemos-Amado
Francisco
F
Domingues
Pedro
P
Ferrer-Correia
A
A
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
D045563:Indolequinones; D007211:Indoles; C091584:aminochrome 1