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Istituto di scienza dell'alimentazione

Torna all'elenco Contributi in rivista anno 2001

Contributo in rivista

Tipo: Articolo in rivista

Titolo: Oxidative conversion of 6-nitrocatecholamines to nitrosating products: a possible contributory factor in nitric oxide and catecholamine neurotoxicity associated with oxidative stress and acidosis.

Anno di pubblicazione: 2001

Formato: Elettronico Cartaceo

Autori: Palumbo, A. Napoletano, A. Carraturo, G. L. Russo, and M. d’Ischia

Affiliazioni autori: Istituto di Sicenze dell' Alimentazione CNR Avellino Stazione Zoologica A. Dohrn Napoli Department of Organic Chemistry and Biochemistry, University of Naples "Federico II", Naples, Italy

Autori CNR:


Lingua: inglese

Abstract: Oxidation of 6-nitrodopamine (1) and 6-nitronorepinephrine (2), as well as of the model compounds 4-nitrocatechol and 4-methyl-5-nitrocatechol, with horseradish peroxidase (HRP)/H(2)O(2), lactoperoxidase (LPO)/H(2)O(2), Fe(2+)/H(2)O(2), Fe(2+)-EDTA/H(2)O(2) (Fenton reagent), HRP or Fe(2+)/EDTA in combination with D-glucose-glucose oxidase, or Fe(2+)/O(2), resulted in the smooth formation of yellowish-brown pigments positive to the Griess assay. In the case of 1, formation of the Griess positive pigment (GPP-1) promoted by HRP/H(2)O(2) proceeded through the intermediacy of two main dimeric species that could be isolated and identified as 3 and the isomer 4, featuring the 4-nitro-6,7-dihydroxyindole system linked to a unit of 1 through ether bonds. Spectroscopic (FAB-MS, (1)H NMR) and chemical analysis of GPP-1 indicated a mixture of oligomeric species related to 3 and 4 in which oxidative modification of the nitrocatechol moiety of 1 led to the generation of reactive nitro groups supposedly linked to sp(3) hybridized carbons. In the pH range 3-6, GPP-1 induced concentration- and pH-dependent nitrosation of 2,3-diaminonaphthalene, but very poor (up to 2%) nitration of 600 microM tyrosine. At pH 7.4, 1 exerted significant toxicity to PC12 cells, while GPP-1 proved virtually innocuous. By contrast, when assayed on Lactobacillus bulgaricus cells at pH 3.5, 1 was inactive whereas GGP-1 caused about 70% inhibition of cell growth. Overall, these results hint at novel pH-dependent mechanisms of nitrocatecholamine-induced cytotoxicity of possible relevance to ischemia- or inflammation-induced catecholaminergic neuron damage

Lingua abstract: inglese

Pagine da: 1296

Pagine a: 1305


Chemical research in toxicology American Chemical Society,
Paese di pubblicazione: Stati Uniti d'America
Lingua: inglese
ISSN: 0893-228X

Numero volume: 14

Referee: Ś: Internazionale

Indicizzato da: PubMed [11559046]

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