Investigation of Satureja Hortensis L. as a Possible Source of Natural Antioxidants

Abstract

Natural antioxidants play important roles as health-protecting factors. Antioxidants are also widely used as additives in fats and in food processing to prevent or delay spoilage of foods. Spices have received an increased attention as natural sources of many effective antioxidants. In this study Satureja hortensis L. (summer savory) was examined as a potential source of natural antioxidant compounds. For the isolation of the active components two extraction methods were investigated: conventional Soxhlet extraction and supercritical fluid extraction. Conventional Soxhlet extraction was carried out with organic solvents with different polarities. Supercritical fluid extractions were performed with neat CO2 at two different pressures (300 and 450 bar) at 40 °C. To estimate the antioxidant activity of the extracts, 1,1-diphenyl-2-picrylhydydrazyl (DPPH) assay was used. The results were reported as IC 50%, where IC 50% was defined as the extract concentration required decreasing the initial DPPH concentration by 50%. The antioxidant activity of the extracts obtained with organic solvents decreased in the following order: ethanol 50% £ ethanol 96% £ isopropanol £ ethanol 100% £ acetone £ ethyl acetate £ pentane. The highest antioxidant activity exhibited the extract obtained with ethanol 50% (with an IC 50% value of 14.48 ± 0.02 µg/ml), while the extract obtained with pentane showed the lowest antioxidant activity (with an IC 50% of 98 ± 0.1 µg/ml). The antioxidant activity of the extracts was also compared with the antioxidant activity of butylated hydroxytoluene (BHT). The extract obtained with ethanol 50% showed approximately similar antioxidant activity as BHT (with an IC 50% of 12.86 ± 0.19 µg/ml). Although in the case of the supercritical extraction the antioxidant activity increased with increasing the pressure, it was lower than the antioxidant activity of the extracts performed with organic solvents.