Distinguishing the 5,5-dimethyl-l-pyrroline TV-oxide(DMPO)-OH radical quenching effect from the hydroxyl radical scavenging effect in the ESR spin-trapping method

摘要

The spin-trapping method has been widely accepted to measure the hydroxyl radical scavenging activity in electron spin resonance(ESR)spectroscopy,however,the disappearance of the trapped signal of the 5,5-dimethyl-l-pyrroline N-oxide(DMPO)-OH radical may lead to an erroneous conclusion,as the decreased signal must result from the rapid quenching of the DMPO-OH formed.The DMPO-OH quenching activity of a compound can be measured by tracing the signal decay resulting from its addition after the cessation of DMPO-OH formation.It was found that Fe(II)ions could quench the DMPO-OH radical quite rapidly,and phosphate ions could enhance the DMPO-OH radical quenching activity of the Fe(II)ions.