Antioxidant and Anti-Inflammatory Activities of Essential Oils: A Short Review

Miguel, Maria Graça

One method usually used for the determination of chelating activity uses ferrozine, which can quantitatively from complexes with Fe 2+ . In the presence of other chelating agents, the complex formation is disrupted, giving rise to a decrease of the red colour of the complex ferrozine-Fe 2+ . Measurement of the rate of colour reduction therefore allows estimation of the chelating activity of the coexisting chelator [46] . Essential oils of Myrtus communis, Thymus marschallianus and Thymus proximus generally did not present chelating activity [46, 54] . The sole exception was the essential oils of flowers of myrtle. The authors [46] explained this activity to the presence of eugenol and methyl eugenol in its essential oil, whereas these two components only belong to a minor fraction of leaf and stem essential oils. These dihydroxylated compounds would be necessary to form chelated Fe 2+ . Leaf and stem oils had as main components 1,8-cineole and terpinen-4-ol, monohydroxylated compounds that would be unable to chelate ferrous ions [46] . Concerning the essential oils of spice plants used in a Mediterranean diet, all of them were able to chelate Fe 2+ and did so in a concentration-dependent manner [52] . At all concentrations assayed Rosmarinus officinalis L. and Salvia officinalis essential oils showed the highest values for chelating Fe 2+ . All the oils studied were better chelators of Fe 2+ than ascorbic acid and BHT, used as references [52] .