Kinetic and Thermodynamic study of DPPH scavenging in the presence mixture of Taxol as an anti cancer , Ascorbic acid as an antioxidant

Reactions of free radicals and reactive oxygen species (ROS) with biological molecules in vivo play an important physiological role in manydiseases. 2,2-diphenyl-1-picrylhydrazyl (DPPH) isa stable free radical and often used as substrate to evaluate the antioxidant capacity of an antioxidant.This study was undertaken to investigate the free radical-scavenging and antioxidant activities of Taxol as an anti cancer drug, Vitamin C as anantioxidant and mixture of them. UV-Vis spectrometry method was used to evaluate the ability mixture of Taxol, Vitamin C to scavengeDPPH radical. The kinetic parameters such as rateconstant , activation energy and thermodaynamic parameters such as anthalpy and anthropy inexperimental conditions were calculated. The rateconstants of the ( H ) atom abstraction by DPPH, in the presence mixture of Taxol , Vitamin C wasobtained 0.0918 s-1,under pseudo-first-order conditions at 25 oC . Anthalpy , anthropy for mixture of them were obtained -6.242 Kcal.mol-1 -83.956 cal K-1 mol -1 respectively