Perfil fitoquímico, atividade antioxidante e antimicrobiana de extratos de espécies da flora amazônica coletadas na região de influência socioambiental da UHE-Tucuruí

Abstract

With over 56,000 plant species, Brazil has one of the richest in the world, encompassing nearly 19% of the world's flora, excluding fungi. Much of this resource is found in the Amazon, which is a region with the highest biodiversity on the planet. However, due to various anthropic actions, knowledge, conservation and numerous native species with biotechnological potential can be lost. In this sense, the present study aimed to analyze the phytochemical profile, antioxidant and antimicrobial activity of peel extracts and fruit seeds of three species of the Amazonian flora, prepared from different extractive techniques. For this, vegetable matrices were obtained from the peel and seeds of fruits of Poraqueiba sericea, Garcinia macrophylla and Platonia insignis, the extraction methods applied were hot, using Sohxlet, and cold using hexane, methanol and hydroalcoholic system. (50:50) as solvents. Phytochemical screening tests were performed to identify the main classes of secondary metabolites present in plant structures. Antioxidant activity was evaluated by applying the DPPH, ABTS and FRAP methods and the antimicrobial potential was determined by the plate diffusion disc method. The hot hydroalcoholic extract of G. macrophylla seeds presented the best yield (11.40%). All species presented a considerable range of secondary metabolite classes, with emphasis on the cold hydroalcoholic extract of G. macrophylla (EHA-Gm) seeds, which presented the highest variability (9 classes). Regarding antioxidant activity, the EHA-Gm fraction showed activity of 685.53 (± 7.38x10-4 ) μmol Fe (II) .g-1 extract, in the concentration of 0.1875 mg.mL-1 , being the most active among the extracts tested by the FRAP method. This same fraction presented the lowest efficiency concentration to reduce the DPPH radical by 50% (EC50) (97.31 ± 5.98 × 10-2 µg / mL). In the antimicrobial assays, the tested extracts showed positive inhibition response against strains of Bacillus subtilis, Candida glabrata and Cyanobacteria Synechocystis sp. and Synechococus sp. The present study demonstrated that P. sericea, P. insignis and G. macrophylla species can be considered as promising sources of bioactive compounds. Notably G. macrophylla, which stood out in the antimicrobial and antioxidant tests performed during this study.