Antioxidant Activity and Chemical Composition of Essential Oils of some Aromatic and Medicinal Plants from Albania

Abstract

The chemical compositions have been investigated of the volatile oils of nine populations of six species from Albania, namely Artemisia absinthium, Calamintha nepeta, Hypericum perforatum, Sideritis raeseri subsp. raeseri, Origanum vulgare subsp. hirtum from two wild populations, and Salvia officinalis (sage) from two wild and one cultivated population,. The essential oils were obtained by hydrodistillation and their analyses were performed by GC–MS. The major constituents were: A. absinthium: neryl isovalerate (19.5%), geranyl isobutanoate (16.4%) and carvacrol (8.8%); C. nepeta: pulegone (31.7%), spathulenol (20.0%) and isomenthone (12.7%); H. perforatum: caryophyllene oxide (31.0%), δ-selinene (10.5%) and carvacrol (10.4%); O. vulgare: carvacrol (81.0, 78.6%), γ-terpinene (5.5, 7.1%) and p-cymene (4.9, 4.1%) for O. vulgare originating from Tepelena and Vlora, respectively; S. raeseri: carvacrol (36.7%), caryophyllene oxide (17.8%), β-caryphyllene (8.7%), spathulenol (7.7%) and myrtenol (6.4%); S. officinalis: camphor (40.2, 47.8, 45.9%), α-thujone (19.2, 22.2, 13.7%), eucalyptol (5.4, 2.6, 6.0%), camphene (5.8, 6.1, 3.9, %), borneol (2.1, 2.9, 5.7%) and bornyl acetate (3.3, 1.4, 5.6%) for samples originating from Tepelena, Tirana and Vlora, respectively. The essential oils were also tested for their free radical scavenging activity using the following in vitro assays: i) interaction with the free stable radical of DPPH (1,1-diphenyl-2-picrylhydrazyl), and ii) inhibition of linoleic acid peroxidation with 2,2'-azobis-2-methyl-propanimidamide, dihydrochloride (AAPH). Finally, their inhibitory activity toward soybean lipoxygenase was evaluated, using linoleic acid as substrate. The essential oil of O. vulgare (OV-VL) presented the highest interaction with the stable radical DPPH (76.5%), followed by that of A. absinthium (54.7%). O. vulgare (OV-TP) and A. absinthium showed high anti-lipid peroxidation activity, 97.5% and 96.5%, respectively, higher than that of the reference compound trolox (73.0%). Only the tested sample of O. vulgare (OV-VL) significantly inhibited soybean lipoxygenase (54.2%).