Myrtus communis L. Infusions: The Effect of Infusion Time on Phytochemical Composition, Antioxidant, and Antimicrobial Activities

In traditional medicine, myrtle (Myrtus communis L.) is frequently consumed as an infusion and decoction. In this study, we investigate the phenolic and volatile compositions and antioxidant and antibacterial activities of leaf infusions prepared during 3 different times. The total phenolics contents (146.74 to 179.55 mg GAE/g DM) varied significantly between infusions. Eleven phenolic compounds were identified by reversed-phase high-performance liquid chromatography. Phenolic acids (7.64 to 14.28 mu mol/g DM) and flavonol glycosides (7.05 to 12.11 mu mol/g DM) were the major phenolic fractions of infusions. Significant quantitative variation in 6 phenolic components was observed between infusions. Sixteen volatile components were identified by gas chromatography (GC) and GC mass spectrometry analyses. The main constituents were 1,8-cineole (42.58% to 51.39%), a-terpineol (9.45% to 9.72%), methyl eugenol (6.69% to 7.11%), and linalool (5.91% to 6.06%). Quantitative variations of the volatile components of the analyzed oils in relation to the infusion time were observed. The antioxidant properties of infusions, assayed through DPPH (2,2- diphenyl-1-picrylhydrazyl) method, beta-carotene bleaching test, chelating effect on ferrous ions, and ferric reducing power method, were considerable and varied according to the infusion time. Myrtle infusions exhibited a substantial antimicrobial activity against 6 tested bacteria.