Faculty Collaboration Database

An ESR study of the nitroxide radical of pentastarch-conjugated deferoxamine. Free Radic Biol Med 1990;9(3):211-8

Date

01/01/1990

Pubmed ID

2177027

DOI

10.1016/0891-5849(90)90030-m

Scopus ID

2-s2.0-0025064707 (requires institutional sign-in at Scopus site)   15 Citations

Abstract

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.

Author List

Pieper GM, Gross GJ, Kalyanaraman B

Author

Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Deferoxamine
Deoxyribose
Electron Spin Resonance Spectroscopy
Free Radical Scavengers
Hydrogen Peroxide
Hydrolysis
Hydroxides
Hydroxyl Radical
Nitrogen Oxides