Antioxidant status and human health. Use of cyclic voltammetry for the evaluation of the antioxidant capacity of plasma and of edible plants.

The low molecular weight antioxidants (LMWA) play a major role in protecting biological systems against reactive oxygen-derived species (ROS), and reflect the antioxidant capacity of the system. The cyclic voltammetry (CV) has been conveniently used and validated for the quantitation of the antioxidant capacity of the LMWA of blood plasma, tissue homogenates, and plant extracts. The CV tracing provides the biological oxidation potential (E and E1/2 which relate to the nature of the molecule(s)), the intensity of the anodic current wave (Ia), and its area S (both relate to the concentration of the molecule(s)). The components of the first anodic wave of plasma were identified by comparison with HPLC-electrochemical detection. CV together with another plasma parameter R, which reflects the level of oxidized ascorbate, were used for the evaluation of the antioxidant status and the oxidative stress in healthy subjects and in chronic (diabetes mellitus) and acute patients (subjected to total body irradiation prior to bone marrow transplantation). These methodologies could be widely employed for rapid evaluation of subjects, in health and disease, for monitoring of their response to treatment and nutritional supplementation, and for screening of specific populations.