Generation of superoxide radical, hydrogen peroxide and hydroxyl radical during the autoxidation of N,N,N',N'-tetramethyl-p-phenylenediamine.

The autoxidation of N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) at neutral pH has been shown to generate superoxide radical and hydrogen peroxide. The rate of formation of these species was increased in the presence of certain iron and copper compounds; in the presence of iron complexed with EDTA, hydroxyl radical was also produced. Hydrogen peroxide was detected in erythrocytes incubated with TMPD and these cells suffered oxidative damage as reflected by methaemoglobin formation and glutathione depletion; the one-electron oxidation product of TMPD, Wurster's Blue, was equally effective in producing such changes in erythrocytes. N-Methylated p-phenylenediamines are known to be mutagenic and myotoxic, and it is suggested that 'active oxygen' species may be involved in the initiation of these harmful effects.