An ESR study of the nitroxide radical of pentastarch-conjugated deferoxamine

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Free Radical Biology and Medicine; (USA)

DOI:https://doi.org/10.1016/0891-5849(90)90030-M· OSTI ID:6139782

Pieper, G M; Gross, G J; Kalyanaraman, B ^[1]

---

1. Medical College of Wisconsin, Milwaukee (USA)

At higher concentrations, deferoxamine (DFO) reacts with hydroxyl radicals to produce a stable nitroxide free radical. Formation and decay of this nitroxide radical was investigated and compared with a novel modified pentastarch conjugate of DFO (MPS-DFO). Photolytic generation of hydroxyl radicals from H2O2 in the presence of free DFO produced a nitroxide radical with coupling constants of aN = 8.0 G and aH = 6.5 G. Under the same experimental conditions, equimolar concentrations of MPS-DFO produced an ESR signal of reduced intensity while iron-saturated MPS-DFO produced no signal. Incubation of free DFO with pentastarch (i.e., without conjugation) greatly decreased the intensity of the nitroxide radical signal. Using a spin-trapping technique with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), the pentastarch vehicle was shown to inhibit the DMPO-OH adduct formation. The decay of the DFO nitroxide radical decayed with a second-order rate constant while that of MPS-DFO decayed with a first-order rate constant. Thus, a novel derivative of DFO may provide some additional benefit in limiting DFO nitroxide radical formation and might explain the reported reduced in vivo toxicity of MPS-DFO relative to free DFO.

• OSTI ID: 6139782
• Journal Information: Free Radical Biology and Medicine; (USA), Journal Name: Free Radical Biology and Medicine; (USA) Vol. 9:3; ISSN FRBME; ISSN 0891-5849
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOSYNTHESIS
CHALCOGENIDES
CHELATING AGENTS
ELECTRON SPIN RESONANCE
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
MAGNETIC RESONANCE
METABOLISM
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
PEROXIDES
RADICALS
RESONANCE
SYNTHESIS