In this review, we briefly summarize the reliability of the density functional theory (DFT)-based methods to accurately predict the main antioxidant properties and the reaction mechanisms involved in the free radical–scavenging reactions of chemical compounds present in food. The analyzed properties are the bond dissociation energies, in particular those involving OH bonds, electron transfer enthalpies, adiabatic ionization potentials, and proton affinities. The reaction mechanisms are hydrogen-atom transfer, proton-coupled electron transfer, radical adduct formation, single electron transfer, sequential electron proton transfer, proton-loss electron transfer, and proton-loss hydrogen-atom transfer. Furthermore, the chelating ability of these compounds and its role in decreasing or inhibiting the oxidative stress induced by Fe(III) and Cu(II) are considered. Comparisons between theoretical and experimental data confirm that modern theoretical tools are not only able to explain controversial experimental facts but also to predict chemical behavior.

Structural features, antioxidant ability and UV-Vis absorption properties of a series of coumarin–chalcone derivatives have been elucidated by means of density functional theory.

Excitation into the ¹ CT absorption band of a spin–orbit charge transfer ISC triplet photosensitizer increases the anti-Stokes shift in TTA upconversion.