Quantification of the Antioxidant Capacity of Different Molecules and Their Kinetic Antioxidant Efficiencies

摘要

A kinetic method has been developed to determine the antioxidant capacity of a variety of molecules. In this method, named the enzymatic kinetic method, the free radical of ABTS is generated continuously in the reaction medium by a peroxidase/ABTS/H2O2 system. The presence of an antioxidant in the solution provokes a lag period in the accumulation of the free radical in the medium, and by studying this lag period it is possible to calculate the antioxidant capacity of the molecule in question. This antioxidant capacity, named the primary antioxidant capacity, will be quantified by n, the number of electrons donated per molecule of antioxidant, the effective concentration, EC50, and the antioxidant or antiradical power (ARP) (ARP = 1/EC50 = 2n). If the products arising from the reaction between the antioxidant and the free radical evolve by consuming more radical, a secondary antioxidant capacity is generated. To calculate this, a nonenzymatic test is proposed.