kinetic study of dpph scavenging in the presence of mixture of zinc and vitamin c as an antioxidant

reactions of free radicals and reactive oxygen species (ros) with biological molecules in vivo play an important physiological role in many diseases. 2,2-diphenyl-1-picrylhydrazyl (dpph) is a stable free radical and often used as a routine reagent to evaluate the antioxidant capacity of an antioxidant. this study was undertaken to investigate the free radical-scavenging and antioxidant activities of zinc, vitamin c and mixture of them. uv-vis spectrophotometry method was used to evaluate the ability of zinc, vitamin c and mixture of them to scavenge dpph radical. the kinetic parameters such as rate constant and activation energy in experimental conditions were calculated. the rate constants of the h atom abstraction by dpph (), in the presence of zinc, vitamin c and mixture of them were obtained (0.4209, 2.092 and 1.82 min -1 ) respectively, under pseudo-first-order conditions at 25 o c.