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Spin trapping of superoxide by diester-nitrones
Ahmad Allouch1, Valérie Roubaud, Robert Lauricella
1Laboratoire TRACES, case 541, Universités d'Aix-Marseille 1 et 3, Faculté de St. Jérôme, 13397 Marseille cedex 20, France. tuccio@up.univ-mrs.fr
Organic & Biomolecular Chemistry
|June 25, 2005
Summary
The study compared nitrone spin traps for superoxide detection. DEPO and EMPO showed superior performance, with DEPO effective at low concentrations and EMPO preferred at higher concentrations.
Area of Science:
- Analytical Chemistry
- Organic Chemistry
Background:
- Superoxide radicals are crucial in biological processes and disease.
- Spin trapping is a key technique for detecting reactive oxygen species like superoxide.
- Nitrone spin traps offer a sensitive method for studying these radicals.
Purpose of the Study:
- To synthesize and evaluate a new nitrone spin trap, DEEPyON.
- To compare the kinetic performance of DEEPyON, DEPO, and DEEPN for superoxide detection.
- To assess the impact of diester functionalization on nitrone spin trapping efficiency.
Main Methods:
- Synthesis of the nitrone N-[(1-oxidopyridin-1-ium-4-yl)-methylidene]-1,1-bis(ethoxycarbonyl)ethylamine N-oxide (DEEPyON).
- Kinetic analysis of superoxide trapping and spin adduct decay at pH 7.2.
- Determination of rate constants for trapping and adduct decay reactions.
Main Results:
- Cyclic diester-nitrones (DEPO) exhibited faster trapping and adduct decay than monoester analogues.
- Linear diester-nitrones (DEEPN) showed significantly weaker superoxide trapping capacity.
- DEPO was the only nitrone capable of clear superoxide detection below 0.005 mol dm(-3).
Conclusions:
- DEPO and EMPO are superior spin traps for superoxide detection.
- DEPO is optimal for low spin trap concentrations, while EMPO is preferred for higher concentrations.
- The presence of a second ester group enhances spin trapping efficiency in cyclic nitrones.