Influence of Selected Factors on Antioxidant Properties of Chlorogenic Acid and Kaempferol as Well as Their Binary Mixtures

Abstract

Plants are a rich source of substances with antioxidant properties, including high amounts of polyphenolic compounds, as well as other substances that do not necessarily have antioxidant properties. The presented paper concerns the evaluation of the antioxidant properties of polyphenolics and their binary mixtures in the presence of other components of the system that do not exhibit antioxidant properties. Model systems containing chlorogenic acid and kaempferol were used in the experiments, differing not only in the volume of the alcoholic antioxidant solution in the measurement system, but also in temperature, content of water, metal ions and hydrogen ions. The ability to neutralize free radicals in the systems was estimated using the ABTS method. In light of the presented data, the dominant resultant antioxidant effect in the mixture is antagonism. Its value depends not only on the mutual relations of individual compounds, but also on the presence of other components in the tested system, not only antioxidants. The greatest effect on the antioxidant properties was observed for systems containing iron ions, ethanol and in the presence of hydrogen ions. The obtained results indicate an extremely complex nature of the assessment of antioxidant properties, even in seemingly simple measurement systems.