Antioxidant and Oxidative Stress Modulation Properties of Azorella ‎pedunculata Methanolic Extract on A549 Cancer Cells

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Species of the genus Azorella have been widely studied for the presence of secondary metabolites with biological activities. Azorella pedunculata is the most common species of Azorella genus in Ecuadorian moors. The present study evaluated the oxidative stress-protective and antioxidant effects of methanolic extract from A. pedunculata on A549 cells treated with hydrogen peroxide (for induction of oxidative stress). The DPPH assay (2,2-diphenyl-1-picrylhydrazyl) was used to assess the antioxidant activity of the extract. Cell viability for extract-treated cells was assessed by the 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The protective activity against oxidative stress in A549 cells pretreated with the extract and then exposed to H₂O₂ was evaluated by flow cytometry. In addition, gene expression analysis for oxidative stress-related genes superoxide dismutase 2 (SOD-2), and catalase (CAT) was performed with real-time quantitative reverse transcription PCR (RT-qPCR). The extract was cytotoxic at concentrations above 500μg/mL. Pre-treatment with methanolic extract at concentrations of 100 and 250µg/mL significantly decreased ROS (+) cell population, in comparison with the H₂O₂ treatment control. The mRNA levels of assessed genes were also modulated when cells were pretreated with the extract. In comparison with the H₂O₂ control, SOD-2 was up-regulated when cells were pre-treated with the methanolic extract at 100 µg/mL, and CAT was down-regulated when cells were pre-treated with 100 and 250 µg/mL of extract. The methanolic extract of A. pedunculata might exert a protective effect against oxidative stress. Further studies are required to elucidate the molecular mechanisms involved. The findings of this study might be, however, of value for potential biological and medical applications‎‎.