The assessment of the antioxidant capacity of the selected vanillin-based pyrido-dipyrimidines using DPPH assay: in silico approach

Abstract

It is known that pyridine derivatives possess significant biological activity, and that vanillin is a natural aromatic compound with pharmacoecological properties. Earlier research indicated that among the series of synthesized vanillin-based pyrido-dipyrimidine compounds, two of them show significant antioxidative activity. Based on the thermodynamic parameters obtained using the DFT method, the operative mechanism of the reaction of the investigated antioxidants with the DPPH radical was considered . Calculations are done in water, methanol, and benzene, to imitate real experimental conditions, and to examine the reaction mechanisms under the environment of different polarity. HAT and SPLET mechanisms were identified as operative reaction mechanisms. Which reaction pathway is dominant was found to be independent of the nature of the solvent. A molecule with two O-H groups can react through both O-H groups simultaneously, so it shows a higher antioxidant capacity than a molecule with one O-H group, which is in accordance with the experimentally obtained results.