Antioxidant activity of satureja hortensis L. essential oil and its application in safflower oil

ABSTRACT

It has been considered by researchers to study the possibility of replacing chemical food additives [synthetic antioxidants] by natural products [medicinal plants]. This study investigated the antioxidant properties of Satureja hortensis L. essential oil [SHEO] on safflower oil oxidation. Different assays have been used to evaluate the antioxidant activity of SHEO total phenol content [TPC], DPPH, ABTS+, ferric thiocyanate [FTC], beta - 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]. TPC of SHEO was determined to be 293.7 mg gallic acid equivalent in 1 ml of sample and IC[50] 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 microg/ml AscAE =Ascorbic acid equivalent] in 15 min. In FTC and FTC-TBA, 8 mg/ml SHEO showed the highest activity. In beta-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. Antioxidant activities of SHEO concentrations increased in all indices [pandamp; lt; 0.05] and various concentrations were able to slow down the oxidation process