Antioxidant and Antifungal Activities and Characterization of Phenolic Compounds Using HPLC- MS in Empetrum rubrum Vahl ex Willd.

Abstract

In searching for compounds with antioxidant and antifungal activity, our study focused on the subshrub species Empetrum rubrum Vahl ex Willd. (Ericaceae), commonly known as Brecillo or Murtilla de Magallanes. We measured the antioxidant activity of its methanolic extract (MEE) obtained from the aerial parts (leaves and stems). The antioxidant activity of MEE was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cationic radical. Results were expressed in gallic acid and Trolox equivalents for DPPH and ABTS assays, respectively. The antioxidant activities, for the DPPH and ABTS assays, were also calculated as an inhibitory concentration of extract needed to inhibit 50% of the absorbance (IC50 value). The results of IC50 values measured by the DPPH and ABTS methods were 0.4145 mg mL-1 and 0.1081 mg mL-1, respectively. In relation to the antioxidant activity, the total phenolic content (TPC) in MEE was determined by the Folin-Ciocalteu method, and the presence of secondary metabolites groups, including phenolic compounds, was determined by using different standardized test procedures. Phenolic compounds contained in leaves, stems, and fruits of E. rubrum were determined qualitatively by means of high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis. The antifungal activity of MEE obtained from aerial parts of E. rubrum was tested against Rhizoctonia solani. In vitro, mycelial growth of this fungus was reduced from 90% to 100% in the presence of MEE.