Rapid electrochemical method to screen antioxidative capacity of biological matrices (RESAC)

Abstract

One aspect involved in initiation and development of cardiovascular diseases and cancers are oxidative processes, leading to the generation of hydroxyl radicals and peroxyl compounds [1]. There is growing body of evidence that the chemopreventive effects of antioxidants contribute to inactivate „reactive oxygen species“ [2–4]. In all cases, assessment of antioxidant capacity of our food or other biological matrices is of utmost importance. The majority of free radicals are good oxidants. Therefore, a good antioxidant maybe at first a reductant. The wide mixture of antioxidants with varying redox potentials in plant foods may interact in a synergistic manner, enabling effective protection against oxidation at low concentration levels [5]. Measurement of electrochemical oxidizability should be an appropriate method to assess antioxidant capacity of a biological sample. The aim of the present study was to apply a recently developed electrochemical method for a rapid screening of antioxidant capacity (RESAC) of biological matrices. The electrochemical detector used was equipped with a glassy carbon electrode, operating at a potential of +600 mV. Calibration of the electrochemical method with common photometric standard methods DPPH [6] and FRAP [7] has been done. Results obtained indicate a good correlation between RESAC and these conventional photometric methods (DPPH r=0,935, n=12; FRAP r=0,992, n=12). After calibration, applicability of the method has been shown with selected tea and green coffee samples. The RESAC-method is a rapid and convenient assay based on electrochemical oxidation for the assessment of antioxidant capacity. The method is well suited for quality and specification control and may facilitate future studies regarding alteration of antioxidant capacity during growth, storage and processing of food or medicinal plants.