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DOI: 10.1055/s-0034-1395056
Antioxidant and antigenotoxic properties of Solidago microglossa (Brazilian arnica)
Solidago microglossa DC, popularly known as Brazilian arnica, is a native plant from South America where is used in a similar way as Arnica montana, to treat inflammation and to accelerate wound healing. In this work we studied some pharmacological activities of the phenolic extract of S. microglossa (SME), using the model eukaryotic organism Saccharomyces cerevisiae (Sc). S. microglossa biomass (aerial part) was extracted with methanol 80% and the phenolics analyzed by HPLC-DAD. The major compounds found were caffeoylquinic acids and quercetin derivatives. Sc cells were insulted with H2O2 in the presence of different concentrations of SME. H2O2-dependent loss of viability was attenuated by the presence of low concentrations of SME (30 ng/ml), in co-incubation and pre-incubation experiments, evidencing an antioxidant activity of the extract. Moreover, SME prevented oxidative DNA damage of Sc cells in a dose dependent manner (COMET assay). To investigate the mechanism of antigenotoxicity, the Sc mutants yap1 and sod1, affected in the oxidative stress response, were used. Both strains were significantly more sensitive, when assayed for viability, in the presence of SME and H2O2 than the wild type. To analyze induction of DNA repair by SME, yeast cells were incubated with the extract after H2O2 treatment. DNA damage repair was more rapid in Sc cells post-treated with SME than the control. These results suggest that the SME has an antioxidant effect in cells and has also the property of induction of the DNA repair. Accordingly, Sc treated with SME displayed a significant decrease of fluorescence, with the redox-sensitive probe dichlorofluorescein diacetate, compared to cells treated with hydrogen peroxide, which correlates with results of antigenotoxicity test. Our data provide evidence for the use of S. microglossa in folk medicine.
Acknowledgements: This work is supported by national funds by FCT – Portuguese Foundation for Science and Technology, under the project PEst-OE/AGR/UI4033/2014.