Mexican medicinal and aromatic plants have potential for their different uses and applications. Such is the case of Mexican arnica, which has reported different biological activities [1],[2]. This attributed to its chemical composition, mainly the phenolic compounds. The study of the application of biophysical methods in the agricultural sector has increased. In particular, treatments using electromagnetic field [3]. There is a history that the quality of electromagnetic radiation can affect pigment biosynthesis [4]. With that background the objective of this work was to apply electromagnetic field to plants of Mexican arnica (Heterotheca inuloides Cass.) and evaluate their impact on their content of phenolic compounds. Arnica seedlings obtained in Ozumba State of Mexico, were subjected to electromagnetic field treatments during eight exposure times: 30 sec 1, 5, 10, 15, 20, 30, 45 minutes and a control treatment. Three applications of the treatments were made every 15 days. The seedlings were transplanted in the field at room temperature. The content of phenolic acids and flavonoids were obtained by HPLC [Fig. 1]. There were significant differences between treatments, the highest accumulation of gallic acid (20 min exposition; 0.79 µg/mL), chlorogenic acid (45 min exposition; 222 µg/mL), syringic acid (30 min;1.61 µg/mL), vanillic acid (20 min exposicion;1.35 µg/mL), caffeic acid (30 min exposicion;1.53 µg/mL), rutin (10 min exposition; 918 µg/mL), phloridzine (10 min exposition; 5845 µg/mL), miricetin (10 min exposition;25.35 µg/mL), quercetin (5 min of exposition, 11.82 µg/mL).
Fig. 1 Chromatogram for the identification of Mexican arnica flavonoids by HPLC.
