Evaluation of the antioxidant activity of the essential oils from Cantinoa carpinifolia (Benth.) and Lippia origanoides (Kunth.) by various methods

The essential oils from Cantinoa carpinifolia (Benth.) and Lippia origanoides (Kunth.) were obtained by hydrodistillation. The constituents were determined by GC-MS and GC-FID. The antioxidant activities were evaluated by the ABTS, DPPH and hydroxyl radicals, phosphomolybdenum complex, reducing power, β-carotene/linoleic acid and the TBARS methods. Analysis of variance and the Scott–Knott test of the means at 5% were performed. The principal constituents in the essential oil from C.carpinifolia were α-thujone (32.15%) and β-thujone (22.22%), whereas carvacrol (41.51%), p-cymene (18.36%) and γ-terpinene (17.03%) were obtained from L.origanoides. The respective IC50 for the essential oils from C. carpinifolia and L.origanoides in the ABTS tests were >1000 and 110 µg mL−1; DPPH (110 and >1000 µg mL−1), hydroxyl (636 and 484 µg mL−1), β-carotene (>2000 and 215 µg mL−1) and TBARS (778 and 527µg mL−1). The L. origanoides essential oil was the most effective antioxidant.