Avaliação da atividade antioxidante e antimicrobiana de extratos de Xanthosoma sagittifolium

Abstract

Plants can be used as sources of minerals, vitamins, proteins, as well as antioxidants and antimicrobials. Species such as cocoyam (Xanthosoma sagittifolium) can be good sources of antioxidants and antimicrobials, because it is a species rich in vitamin C, lycopene, carotenoids and chlorophyll. In this sense, the present work was carried out with the objective of investigating the antioxidant and antimicrobial activities of ethanolic extract of leaves of X. sagittifolium. New leaves of cocoyam were collected in the Patos de Minas, MG, and the extract was obtained in ethanol 70 %. The content of phenolic compounds was determined in triplicate using the Folin-Ciocalteu reagent and the total phenolic values were expressed as gallic acid equivalents. The total flavonoid content was determined in triplicate by the colorimetric method, using quercetin as the standard flavonoid for the construction of the calibration curve. The antioxidant capacity of four dilutions (0.5, 1, 5 and 50 mg / mL) of the extract was determined by colorimetric method, based on the transfer of electrons to the radical DPPH, in methanol solution, using Trolox as a reference antioxidant. For the evaluation of the antibacterial activity, the disc diffusion test with standard strains of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was used. The results showed that cocoyam has a high content of phenolic compounds and flavonoids, with a high rate of antioxidant activity. However, it did not present antimicrobial activity for the strains of bacteria evaluated. Therefore, it is suggested that the species is an important source of biologically active molecules and may be used to minimize or prevent oxidative damage.