Composition and antioxidant activities of Iranian Pulicaria gnaphalodes essential oil in Soybean oil.

The essential oil from aerial parts of Pulicaria gnaphalodes was studied in soybean oil. The aim of this study was to evaluate the antioxidant activitiey of Iranian Pulicaria gnaphalodes essential oil in soybean oil during the storage period. The essential oil obtained from Pulicaria gnaphalodes by hydrodistillation and analyzed by GC/Mass. Fifty-eight compounds representing 90.7% of total was identified. Main ingredient in the oil were involved α -Pinene (30.2%), 1,8-Cineole (12.1%), Beta-Citronellol (9.6%), Mertenol (6.6%), α-Terpineol (6.1%), 4-Terpineol (5.9%) and Chrysanthenone (2.9%). Different concentrations (0.200, 400 and 800 ppm) of essential oil and β hydroxyl toluene (BHT; 100 and 200 ppm) was added to soybean oil and incubated for 35 days at 65°C. Peroxide values (PVs) and thiobarbitoric acid-reactive substances (TBARs) levels were measured every week during the time period of the study. Moreover, antioxidant capacity of the essential oil was determined using 1,1 diphenyl-2- picryl hydrazyl (DPPH) and β-carotene-linoleic acid methods. Values were compared among groups in each incubation time using ANOVA test. Results revealed that DPPH β-carotene-linolic acid assay findings on the P. gnaphalodes essential oil were lower than these of synthetic antioxidant, BHT. Moreover, during the incubation time, P. gnaphalodes essential oil lowered PVs and TBARs levels when compared to the control (p<0.001). According to our results essential oil was less effective than synthetic antioxidant. Therefore it may be used as a food flavor, natural antioxidant and a preventive agent for many diseases caused by free radicals.