Cautionary note for DMPO spin trapping in the presence of iron ion

Makino, Keisuke; Hagiwara, Takuya; Hagi, Akifumi; Nishi, Masatoshi; Murakami, Akira

doi:10.1016/0006-291x(90)91556-8

Cited by 133 publications

(77 citation statements)

References 11 publications

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“…EMPO was used instead of DMPO because the superoxide, hydroxyl, and thiyl radical adducts are more readily distinguished and because its superoxide radical adduct is more stable and does not spontaneously decay to a hydroxyl radical adduct signal (Olive et al, 2000;Zhang et al, 2000) as is observed with the DMPO-superoxide adduct (Thornalley, 1986;Makino et al, 1990;Hanna et al, 1992). We report that MAQ-NOH generated an EMPO-hydroxyl radical adduct (Fig.…”

Section: Discussionmentioning

confidence: 68%

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Bolchoz

Gelasco

Jollow³

et al. 2002

J Pharmacol Exp Ther

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Primaquine is an important antimalarial drug that is often doselimited in therapy by the onset of hemolytic anemia. We have shown recently that an N-hydroxy metabolite of primaquine, 6-methoxy-8-hydroxylaminoquinoline (MAQ-NOH), is a directacting hemolytic agent in rat red cells and that the hemolytic activity of this metabolite is associated with GSH oxidation and oxidative damage to both membrane lipids and skeletal proteins. To determine whether the formation of free radicals may be involved in this process, rat red cells (40% suspensions) were incubated with hemolytic concentrations of MAQ-NOH (150 -750 M) and examined by EPR spectroscopy using 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (EMPO) as a spin trap. Addition of MAQ-NOH to red cell suspensions containing 10 mM EMPO gave rise to an EPR spectrum with hyperfine constants consistent with those of an EMPO-hydroxyl radical adduct standard. Of interest, formation of EMPO-OH was constant for up to 20 min and dependent on the presence of erythrocytic GSH. Although no other radical adduct signals were detected in the cells by EPR, spectrophotometric analysis revealed the presence of ferrylhemoglobin, which indicates that hydrogen peroxide is generated under these experimental conditions. The data support the hypothesis that oxygen-derived and possibly other free radicals are involved in the mechanism underlying MAQ-NOH-induced hemolytic anemia.Hemolytic anemia and methemoglobinemia are well recognized dose-limiting side effects in the therapeutic use of arylamine drugs, such as primaquine and dapsone (Beutler, 1969). Because these compounds are not hemotoxic when incubated with red cells in vitro, it has long been appreciated that metabolites are responsible for the onset of the hemolytic response. In the cases of aniline (Harrison and Jollow, 1986), dapsone (Grossman and Jollow, 1988), and phenacetin (Jensen and Jollow, 1991), we have shown that the hemolytic metabolites are their N-hydroxy derivatives. Primaquine metabolism, on the other hand, is relatively more complex, and the metabolites that mediate the hemotoxic responses have not been identified. A variety of known and putative phenolic metabolites of primaquine are redox-active and therefore have the potential to mediate primaquine hemotoxicity (Strother et al., 1984;Baird et al., 1986;Fletcher et al., 1988;Agarwal et al., 1991); however, direct evidence for their hemolytic activity is lacking. We have recently explored an alternative hypothesis-that primaquine hemotoxicity is mediated by an N-hydroxylated metabolite, 6-methoxy-8-hydroxylaminoquinoline (MAQ-NOH).Although the mechanism underlying the damage and removal of red cells by hemolytic N-hydroxylamines remains unclear, oxidative stress has long been considered to play a prominent role in the process (for review, see Beutler, 1971). This concept is based on the well known association of hemotoxicity with oxidation of erythrocytic GSH (to glutathione disulfide and glutathione protein-mixed disulfides), with methemoglobin f...

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Section: Discussionmentioning

confidence: 68%

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Bolchoz

Gelasco

Jollow³

et al. 2002

J Pharmacol Exp Ther

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“…Commun. 172, 1073(1990), and a major product was isolated by RPLC.Based on 'H, I3c NMR and MS measurements, the structure of the major product was assigned to 1-hydroxy-5,5-dimethyl-1-pyrrolid-2-one (HDMPN) having a hydroxamic acid structure. Temperature dependence of NMR spectra and careful analysis of the fragmentation patterns in MS further revealed that HDMPN was present in equilibrium with 2-hydroxy-5,s-dimethyl-1-pyrroline-N-oxide (HDMPO), a tautomer of HDMPN.…”

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confidence: 99%

Mechanistic studies on the formation of aminoxyl radicals from 5,5-dimethyl-1-pyrroline-N-oxide in Fenton systems. Characterization of key precursors giving rise to background ESR signals

Makino¹,

Hagi²,

Ide³

et al. 1992

Can. J. Chem.

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KEISUKE MAKINO, AKIFUMI HAGI, HIROSHI IDE, AKIRA MURAKAMI, and MASATOSH~ NISHI. Can. J. Chem. 70, 2818Chem. 70, (1992.To assign unidentified ESR signals obtained in a Fenton system with a spin trap, 5,s-dimethyl-1-pyrroline-N-oxide (DMPO), fundamental reactions of DMPO have been thoroughly investigated. When the concentration of Fe2+ in Fenton systems exceeded 1% of that of DMPO, background ESR signals totally distinguishable from 2-hydroxy-5,sdimethyl-1-pyrrolidinyloxy (DMPO-OH) appeared, and simultaneously absorbance at 520 nm increased, which was characteristic of hydroxamic acids complexed with Fe3+. To prove the postulated formation of hydroxamic acid as a key intermediate, DMPO was subjected to Fenton reaction or was treated with Fe3+ in aqueous solution to produce DMPO-OH (Makino et al. Biochem. Biophys. Res. Commun. 172, 1073(1990), and a major product was isolated by RPLC.Based on 'H, I3c NMR and MS measurements, the structure of the major product was assigned to 1-hydroxy-5,5-dimethyl-1-pyrrolid-2-one (HDMPN) having a hydroxamic acid structure. Temperature dependence of NMR spectra and careful analysis of the fragmentation patterns in MS further revealed that HDMPN was present in equilibrium with 2-hydroxy-5,s-dimethyl-1-pyrroline-N-oxide (HDMPO), a tautomer of HDMPN. It has also been shown that the oxidation of DMPO yielding HDMPN and HDMPO occurs via DMPO-OH and is driven by Fe3'.. 'These oxidation products (HDMPN and HDMPO) were readily converted to the corresponding ESR visible aminoxyl radicals by oxidation and 'OH addition in aqueous solution, respectively, and superimposition of the ESR signals arising from these radicals accounts for the background signals observed in Fenton systems with DMPO as a spin trap. The method of spin trapping is a powerful tool to detect short-lived free radicals that are not detectable by conventional ESR.' In this method, through reaction with spin traps, short-lived free radicals are converted to relatively stable 'Author to whom correspondence may be addressed. 2~bbreviations: ESR, electron spin resonance spectroscopy; DMPO, 5,5-dimethyl-1 -pyrroline-N-oxide; 'OH, hydroxyl radical; DMPO-OH, 2-hydroxy-5,s-dimethyl-1-pyrrolidinyloxy; HDMPN, 1-hydroxy-5,5-dimethyl-1-pyrrolid-2-one; NMR, nuclear magnetic resonance spectroscopy; M3P0, 2,5,5-trimethyl-lpyrroline-N-oxide; EIMS, electron ionization mass spectrometry; TMS, tetramethylsilane; TSP-d,, 3-(trimethylsily1)propionicaminoxyl radicals (spin adducts) that are ESR detectable (1). Recently this method has been widely applied to the detection of free radicals in biological systems in attempts to correlate the free-radical formation to the initiation of various diseases (2) since a large body of accumulated evidence indicates that free-radical-induced damage of cellular constit-2,2,3,3-d, acid, sodium salt; DMPO-OOH, 2-hydroperoxy-53-dimethyl-1 -pyrrolidinyloxy; MS, mass spectrometry; RPLC, high performance reversed phase liquid chromatography; amu, atomic mass unit; HDMPO, 2-hydroxy-5,5-dimethyl-1-pyrroline-N-oxide...

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“…Supplementation of air with 0.5% CO 2 , however, inhibited color bleaching (Figure 4). When 860 mM ethanol, a ·OH scavenger, was added [10] the color of methylene blue in the culture barely changed. In addition, this system was also able to reduce the color of humic acid, which does not decompose readily (data not shown).…”

Section: Decolorization Of Methylene Blue By Microalgae Chlorella Vulmentioning

confidence: 99%

Decolorization of Organic Compounds by Controlled Microalgal Culture

Hirayama¹

2017

Agrotechnol

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Cautionary note for DMPO spin trapping in the presence of iron ion

Cited by 133 publications

References 11 publications

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Primaquine-Induced Hemolytic Anemia: Formation of Free Radicals in Rat Erythrocytes Exposed to 6-Methoxy-8-hydroxylaminoquinoline

Mechanistic studies on the formation of aminoxyl radicals from 5,5-dimethyl-1-pyrroline-N-oxide in Fenton systems. Characterization of key precursors giving rise to background ESR signals

Decolorization of Organic Compounds by Controlled Microalgal Culture

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