Study of antioxidant activity of pyrimidinium betaines by DPPH radical scavenging method

Abstract

The aim of this investigation was the study of the effect of some kinetic factors on the antioxidant activity of some synthesized pyrimidinium betaines, using 2, 2-diphenyl-1-picrylhydrazy (DPPH) free radical scavenging method. These betaines are bicyclics 1, 2 and monocyclic 3. We investigated the effect of concentration and reaction time on the antioxidant activity of these compounds and some standard antioxidants. All tested compounds were found to be active as DPPH scavengers but concentrations and reaction times influenced deeply the evaluation. At high concentrations, compound 3 is the best antioxidant compared to all other betaines. Reaction time is one of the most important criteria in this reaction. In comparison with standard antioxidants as ascorbic acid and the synthetic antioxidants butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA), the data shows that, depending on the reaction time used, a different activity of the compounds is obtained: standard antioxidants react immediately with DPPH, while pyrimidinium betaines require longer reaction times and higher concentrations.