Development and validation of methodologies for the determination of the antioxidant capacity of carotenoids against reactive oxygen and nitrogen species

Abstract

Carotenoids are natural fat-soluble pigments which have important properties for a variety of biological functions contributing to the beneficial actions in living organisms, such as the decrease in the risk of developing various chronic degenerative disorders. These actions are related to the reduction or inhibition of oxidation reactions, through scavenging of reactive oxygen (ROS) and nitrogen (RNS) species overproduced by the organism. Appropriate methodologies to determine the antioxidant capacity of carotenoids by scavenging the most commonly ROS and RNS found in biological systems, which are related to pathophysiological mechanisms, are scarce in the literature. This difficulty is due to the fact that the major applied methods were developed to evaluate the activity of hydrophilic compounds or the interferences provided by carotenoids with the probes used to detect reactive species, overestimating the values found for fluorescence, chemiluminescence and colorimetry. Thus, the purpose of this project is the development and validation of fluorescence, chemiluminescence or colorimetric methodologies to determine the scavenging capacity of carotenoids against ROS and RNS with biological interest. After development and validation of methodologies, different carotenoids will be evaluated in order to understand the relation between the structure characteristics and the antioxidant capacity. Furthermore, the derived compounds from carotenoid degradation as a result of oxidation reactions induced by ROS and RNS will be characterized by high performance liquid chromatography coupled to a diode array and mass spectrometer detectors (HPLC-DAD-MS/MS).