Estimation of Antioxidant Capacity of Some Amidine Derivatives Using DPPH Free Radical Scavenging Assay: An In vitro Study

The main aim of this study was to estimate the antioxidant capacity of some amidine derivatives, and to investigate the effect of some kinetic parameters on their antioxidant activity, using DPPH free radical scavenging method. It was investigated the effect of the concentration and the reaction time on the antioxidant activity of two selected amidines; N, N'-diphenyl benzamidine 1 and N, N'-diphenyl dodecamidine 2 a fatty alkylamidine. The study also investigated the effect of the substituents carried by the amidine moiety on their antioxidant activity. From the results obtained, we noted that all amidines tested are active as DPPH scavengers, but compounds’ concentration and reaction time influenced deeply the evaluation. At different concentrations and in all reaction times applied, antioxidant activity was more significant for amidine 1 with phenyl groups, while amidine 2 with fatty chain showed the lowest activity. In comparison with standard antioxidants, this study showed that, depending on the reaction time and concentrations used, different activity is obtained: standard antioxidants react immediately with DPPH; whereas the synthesized amidines, particularly fatty amidine need longer reaction time and higher concentrations.