Antioxidant Activities, Binding Parameters, and Electrochemical Behavior of Superoxide Anion Radicals Twords 1-Ferrocenylmethylthymine and 1-Ferrocenylmethylcytosine

摘要

Background: An electrochemical method based on cyclic voltametry techniqueswas used to measure the antioxidant activity of two ferrocene-nucleobases.Objective: The present study aims to measure the antioxidant activity of two ferrocene derivativesbearing nucleobases; the technique is based on the reaction of the in-situ electrochemicalgenerated superoxide anion radical with ferrocene-nucleobases.Method: The decrease in the anodic peak current density of the O2 / O2.? redox couple followingthe addition of ferrocene-nucleobases was used to measure the antioxidant activityand binding parameters of 1-ferrocenylmethylthymine and 1-ferrocenylmethylcytosinewith superoxide anion radical.Conclusion: Both 1-Ferrocenylmethylthymine and 1-Ferrocenylmethylcytosine showedhigher antioxidant activity (0.34 ± 0.03 and 0.045 ± 0.02 mg/mL respectively) than that ofstandard antioxidant α-tocopherol (3.04 ± 0.03 mg/mL). The value of the binding free energyranging from -16.1 kJ.mol-1 for 1-ferrocenylmethylthymine to -21.8 kJ.mol-1 for 1-ferrocenylmethylcytosine suggests an electrostatic interaction of superoxide anion radicalwith both compounds which has been found to be the dominant interaction mode. The kineticsof the interaction reaction of the compounds was quantified having second-order rateconstant values equal to 4.0 and 16.5 M-1 s-1 respectively.