Paper Title
Kinetic Parameter Effects on The Antioxidant Activity of Some Amidine Derivatives using DPPH Free Radical Scavenging Assay

Abstract
The main aim of this study was to investigate the effect of some kinetic parameters on the antioxidant activity of some amidine derivatives, such as N, N'-diphenylbenzamidine 1 and N, N'-diphenyldodecamidine 2 a fatty alkylamidine, using DPPH free radical scavenging method. It was investigated the effect of the concentration and the reaction time on the antioxidant activity of the tested compounds. The study also investigated the effect of the substituents 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. Keywords - Antioxidant activity, DPPH, Kinetic parameter, Amidines derivatives.