antioxidant activity of satureja hortensis l. essential oil and its application in safflower oil

background: it has been considered by researchers to study the possibility of replacing chemical food additives (synthetic antioxidants) by natural products (medicinal plants). objective: this study investigated the antioxidant properties of satureja hortensis l. essential oil (sheo) on safflower oil oxidation. methods: different assays have been used to evaluate the antioxidant activity of sheo: total phenol content (tpc), dpph•, abts+•, ferric thiocyanate (ftc), β - carotene bleaching. for evaluation of sheo effect on safflower oil oxidation, peroxide value (pv), conjugated dienes (cd), and tiobarbituric acid (tba) indices were compared with bht (a synthetic antioxidant). results: tpc of sheo was determined to be 293.7 mg gallic acid equivalent in 1 ml of sample and ic50 was 0.71 mg/ml in dpph•. 0.4 and 0.1 mg/ml of sheo at all time (1, 5, 10, 15 min) showed the highest and lowest antiradical abts°+ activity (118.2 and 26.6 μg/ml ascae =ascorbic acid equivalent) in 15 min. in ftc and ftc-tba, 8 mg/ml sheo showed the highest activity. in β-carotene bleaching of 0.1-2 mg/ml sheo, 0.1 has the minimum (%9.02), and 1 and 2 has the maximum inhibitory effects (%34.33 and %36.86 inhibitions). 4 mg/ml of sheo had the highest inhibitory effect in the safflower oil test and that peroxide does not have significant difference with 0.1 mg/ml bht. conclusion: antioxidant activities of sheo concentrations increased in all indices (p< 0.05) and various concentrations were able to slow down the oxidation process.