Abstract <p>The main representatives of the 4-H-pyran series of acids are meconic, comenic, chelidonic and kojic acids. A wide range of physiological activity has been established with respect to these substances, including neuroprotective, anti-inflammatory, immunomodulatory and regenerating activity. A comparative study of the antioxidant activity of these acids in various model systems has been performed using chemiluminescent, spectrophotometric, and fluorescent analysis methods, as well as computational methods of quantum chemistry. It was found that, with respect to lipid, luminol, and pyroxyl radicals, all the acids studied in the work caused a dose-dependent decrease in the intensity of the chemiluminescent reaction, expressed by varying degrees of inhibition for each compound. With respect to the stable radical ABTS^+•, all the studied acids also had an inhibitory effect. The studied compounds showed a chelating effect on Fe²⁺ cations with varying efficiencies and inhibited the development of the Fenton reaction in the model system. The experimental data obtained on the antiradical activity of the studied compounds correlated with the theoretical calculations of their antioxidant potential. The established antioxidant and chelating properties of the basic acids of the 4-N-pyran series allow them to be considered as potential ligands and components in the synthesis of new complex and hybrid compounds.</p>