N,N-Dimethyl-p-phenylenediamine dihydrochloride-based method for the measurement of plasma oxidative capacity during human aging.

N,N-Dimethyl-p-phenylenediamine dihydrochloride (DMPD) is a compound that is normally used to measure the antioxidant potential. In the presence of Fe(3+), it gets converted to DMPD(∙+) radical, which is scavenged by antioxidant molecules present in test samples. In plasma, due to the presence of iron, this method cannot be applied for the measurement of antioxidant potential. The modified DMPD method proposed by us measures with great accuracy the oxidant potential of plasma using the oxidizing effect of plasma to oxidize DMPD into producing a stable pink color. The method is fast and reproducible. We show that plasma oxidative capacity increases significantly during human aging.