title: Dipyrone and aminopyrine are effective scavengers of reactive nitrogen species.
abstract: Reactive nitrogen species (RNS), namely nitric oxide (NO*) and peroxynitrite (ONOO-) are produced in the inflammatory sites and may contribute to the deleterious effects of inflammation. The aim of the present study was to evaluate the putative scavenging effect of a particular group of non-steroidal anti-inflammatory drugs (NSAIDs), the pyrazolone derivatives dipyrone, aminopyrine, isopropylantipyrine, and antipyrine against RNS, using in vitro non-cellular screening systems. The results obtained showed that dipyrone and aminopyrine were highly potent scavengers of NO* and ONOO- while antipyrine exerted little effect and isopropylantipyrine no effect whatsoever against these two RNS and that, in the presence of bicarbonate, the scavenging potencies of both dipyrone and aminopyrine were slightly decreased. It could thus be inferred that the observed scavenging effects may be of therapeutic benefit for patients under anti-inflammatory treatment with dipyrone and aminopyrine in the case of overproduction of RNS. On the other hand, the possible depletion of physiological NO* concentrations, namely at the gastrointestinal tract as well as the formation of reactive derivatives of aminopyrine and/or dipyrone, resulting from their reaction with RNS, may otherwise be harmful for these patients.
authors.affiliation: REQUIMTE, Departamento de Química-Física, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal.
authors.forename: David
authors.initials: D
authors.lastname: Costa
authors.forename: Abel
authors.initials: A
authors.lastname: Vieira
authors.forename: Eduarda
authors.initials: E
authors.lastname: Fernandes
mesh_terms: D000632:Aminopyrine / Q000494:pharmacology*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001639:Bicarbonates / Q000737:chemistry; D004177:Dipyrone / Q000494:pharmacology*; D016166:Free Radical Scavengers; D041981:Gastrointestinal Tract / Q000473:pathology; D007249:Inflammation; D020128:Inhibitory Concentration 50; D008956:Models, Chemical; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000494:pharmacology; D026361:Reactive Nitrogen Species
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001639:Bicarbonates; D016166:Free Radical Scavengers; D026361:Reactive Nitrogen Species; D000632:Aminopyrine; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D004177:Dipyrone