Atividade antioxidante de extratos das folhas da Psidium myrtoides O. Berg

Abstract

Psidium myrtoides O. Berg, popularly known as araçá or purple araçá is a predominantly Brazilian savannah plant, but is found in three phytogeographic domains within Brazil: Caatinga, Cerrado and Mata Atlântica. Its scientific name has some synonyms like Psidium myrsinoides, Guajava myrsinoides, Guajava myrtoides, Myrtus corynantha, Psidium turbinatum, Psidium corynanthum and Corynemyrtus corynantha. This plant was studied due to the fact that other species of the same genus have biological activities, including antioxidant activity. Thus, the objective of this work was to perform the antioxidant analysis of extracts and partitions of Psidium myrtoides leaves. For this determination, the phytochemical prospecting was performed in order to evaluate the classes of compounds present in the samples, detecting the presence of phenolic compounds, terpenes, steroids and sugars. The contents of total phenolic compounds, flavonoids and condensed tannins were quantified by spectrophotometric methods. The antioxidant activity of the samples was quantified by three different methods: 2,2-diphenyl-1-picrihidrazila (DPPH) radical sequestration methods, Oxygen Radical Absorbance Capacity (ORAC) method and also by the Ferric Reducing Antioxidant Power (FRAP). The partition with the highest antioxidant capacity observed for the methods used was the ethyl acetate partition with EC50 3,45 ± 0.48 μg mL-1 (DPPH), with 916,13 µmol trollox equivalent (ORAC) and with 2636,8 µmol trollox equivalent (FRAP) These results of antioxidant activity of P. myrtoides leaves are promising and deserve further chemical and pharmacological investigation, for better use of this Cerrado plant for human use.