Avaliação da atividade antioxidante de carotenoide e compostos fenólicos do pequi (caryocar brasiliense) por diferentes mecanismos vista por DFT

Abstract

Pequi is a tropical fruit rich in carotenoids and phenolic compounds, which have antioxidant properties, and are of great importance for the State of Maranhão, contributing as a source of income for many people in the food, cosmetics and other industries. With regard to this property, the present work seeks to evaluate the activity of inhibiting free radicals of such compounds, through a theoretical study, via Density Functional Theory (DFT), addressing different mechanisms of action. For this purpose, the identified carotenoids and phenolic compounds were identified from the literature, and then the structures of these molecules were downloaded in appropriate databases. These were subjected to quantum optimization calculations, applying the DFT method with the functional B3LYP and the base sets 6-31G (d, p) for carotenoids and 6-311G (d, p) for the phenolic compounds in the Gaussian program. The molecular descriptors, Ionization Energy (EI) and Electronic Affinity (AE) were calculated and used to construct the total electron acceptance-donation map (FEDAM) to identify how the activity of these compounds is processed, and later the Gibbs free energies and binding dissociation energy for evaluation of antioxidant potential. The results obtained indicate that among the carotenoids, β-carotene, and Zeaxanthin had the best antioxidant activity. Regarding phenolic compounds, the Quercetin, Ethyl gallate and quinic acid are those that best exert antioxidant activity.