The role of extracts from Eugenia uniflora L. against metal stress in eukaryotic and prokaryotic models

Abstract This study aims to verify the chelating, antioxidant and cytoprotective activities of Eugenia uniflora in a eukaryotic and prokaryotic model. Ethanolic extract, as well as tannic and flavonoid fractions, were prepared from samples obtained from the species which were analyzed by LC-MS. The antioxidant activity through the FRAP method showed that the tannic fraction had the lowest EC50. The suggested compounds identified in the extract and fractions were quercetin and the derivatives, myricetin, gallic acid, vanillic acid, quinic acid and catechin. Regarding the flavonoid fraction, a reduction in the fungicidal effect was observed. When the ethanolic extract was assayed in the presence of mercury chloride, all fractions showed a cytoprotection in relation to this metal. The sub-allelopathic concentration used was 64 μg/mL. The flavonoid fraction showed cytoprotective activity against aluminum for caulicles and radicles, whereas for the mercury against the radicles at all concentrations. Meanwhile the tannic fraction against aluminum showed a better development in the size of the radicles, the mercury there were differences in the sizes of the radicles and caulicles. The results demonstrated in this work indicate that natural products of Eugenia uniflora are promising sources of natural products with antioxidant and chelating activity.