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

Miguel, Maria Graça

Nevertheless, there are other authors that consider it enough to test using only one method (DPPH) when good antioxidant activity values are found [62, [66] [67] [68] 70] . For example, the authors in [62] found high antioxidant activities of the essential oils of Eucalyptus camaldulensis Dehnh. growing wild in different localities of Sardinia (Italia). The activities changed according to the chemical composition, neverthless generally constituted by p-cymene, 1,8-cineole, β-phellandrene, spathulenol and cryptone in different proportions according to the harvesting place and period. The essential oil of Majorana hortensis L. had appreciable antioxidant activity probably ascrible to carvacrol with positive synergism with other components [66] . Citrus maxima Burm. and Citrus sinensis (L.) Osbeck also had considerable antioxidant activities, despite the chemical differences of their essential oils. Whereas Citrus sinensis oils was predominantly constituted by limonene, in Citrus maxima oil, several components could be identified in significant amounts in the oil (limonene, E-citral, Z-citral and 3,3dimethyl-1-hexene [67] . Heracleum pastinacifolium and Heracleum persicum were described as possessing moderate antioxidant activity, which main components were myristicin and trans-amethole, respectively [68] . Three Mexican Lippia graveolens Kunth. oils with different chemical compositions as well as their microcapsules were evaluated in terms of antiradical activities. The authors concluded that microencapsulation increased the anti-radical activity from fourfold to eightgold [69] . Diverse oils obtained from Origanum vulgare L. subsp. glandulosum (Desf.) collected at different locations of Tunisia showed different but always good abilities for scavenging DPPH radicals. Such results depended on the percentage of phenolic compounds (thymol) present in the oils [71] . In spite of the fact some authors consider that the flower oils of Retama raetam (Forssk.) Webb cultivated in Tunisia presented good antioxidant activity, as measured through the DPPH method, the sole method used by the authors, whereby the IC 50 value was fortyfold superior to that of the reference BHT, nevertheless the apparent relative good activity reported by the authors could be attributed to the relative high percentage of monoterpenes present in the essential oils [72] . A good activity was found by Saei-Dehkordi et al. (2010) [74] for the root oil of Ridolfia segetum (L.) Moris from Tunisia, because the IC 50 values were close to that of BHT. Such antiradical activity could be attributed to the high amounts of two phenyl-propanoids, dillapiole and myristicin [60] .