Antioxidative activity of Rosmarinus officinalis L. essential oil compared to its main components

This study was designed to examine the in vitro antioxidant activities of Rosmarinus officinalis L. essential oil compared to three of its main components (1,8-cineole, alpha-pinene, beta-pinene). GC-MS analysis of the essential oil resulted in the identification of 19 compounds, representing 97.97% of the oil, the major constituents of the oil were described as 1,8-cineole (27.23%), alpha-pinene (19.43%), camphor (14.26%), camphene (11.52%) and beta-pinene (6.71%). The oil and the components were subjected to screening for their possible antioxidant activity by means of 2,2-diphenyl-1-pierylhydrazyl (DPPH) assay and beta-carotene bleaching test. In the DPPH test system, free radical-scavenging activity of R. officinalis L. essential oil, 1,8-cineole, alpha-pinene and beta-pinene were determined to be 62.45% +/- 3.42%, 42.7% +/- 2.5%, 45.61% +/- 4.23% and 46.21% +/- 2.24% (v/v), respectively. In the beta-carotene bleaching test system, we tested series concentration of samples to show the antioxidant activities of the oil and its main components, whereas the concentrations providing 50% inhibition (IC50) values of R. officinalis L. essential oil, 1,8-cineole, alpha-pinene and beta-pinene were 2.04% +/- 0.42%, 4.05% +/- 0.65%, 2.28% +/- 0.23% and 2.56% +/- 0.16% (v/v), respectively. In general, R. officinalis L. essential oil showed greater activity than its components in both systems, and the antioxidant activities of all the tested samples were mostly related to their concentrations. Antioxidant activities of the synthetic antioxidant, ascorbic acid and BHT, were also determined in parallel experiments as positive control. (C) 2007 Elsevier Ltd. All rights reserved.