Electrochemical, UV--visible and EPR studies on nitrofurantoin: nitro radical anion generation and its interaction with glutathione.
This paper deals with the reactivity of the nitro radical anion electrochemically generated from nitrofurantoin with glutathione. Cyclic voltammetry (CV) and controlled potential electrolysis were used to generate the nitro radical anion in situ and in bulk solution, respectively and cyclic voltammetry, UV--Visible and EPR spectroscopy were used to characterize the electrochemically formed radical and to study its interaction with GSH. By cyclic voltammetry on a hanging mercury drop electrode, the formation of the nitro radical anion was possible in mixed media (0.015M aqueous citrate/DMF, 40/60, pH 9) and in aprotic media. A second order decay of the radicals was determined, with a k2 value of 201 and 111 M(-1) s(-1), respectively. Controlled potential electrolysis generated the radical and its detection by cyclic voltammetry, UV--Visible and EPR spectroscopy was possible. When glutathione (GSH) was added to the solution, an unambiguous decay in the signals corresponding to a nitro radical anion were observed and using a spin trapping technique, a thiyl radical was detected. Electrochemical and spectroscopic data indicated that it is possible to generate the nitro radical anion from nitrofurantoin in solution and that GSH scavenged this reactive species, in contrast with other authors, which previously reported no interaction between them.
Núñez-Vergara
L J
LJ
Laboratory of Bioelectrochemistry, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago. lnunez@ll.ciq.uchile.cl
Sturm
J C
JC
Olea-Azar
C
C
Navarrete-Encina
P
P
Bollo
S
S
Squella
J A
JA
D000838:Anions; D003497:Cyclic N-Oxides / Q000737:chemistry; D004563:Electrochemistry; D004572:Electrolysis; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D005978:Glutathione / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009582:Nitrofurantoin / Q000737:chemistry*; D012996:Solutions; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013113:Spin Labels
D000838:Anions; D003497:Cyclic N-Oxides; D005609:Free Radicals; D012996:Solutions; D013113:Spin Labels; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D009582:Nitrofurantoin; D005978:Glutathione