Determination the antioxidant activity and characterization of phenolic compounds of Gundelia Tournefortii L. seed oil

Gundelia Tournefortii L. seed oil could be potent enough to consider as edible oil possessing antioxidant properties. To investigate that, the antioxidant activity of this oil and its effects as a natural antioxidant agent was studied. The oil was extracted by maceration method using ethyl ether as a solvent. Then, DPPH method was applied to investigate the radical scavenging activity of the oil and its fractions. Peroxide (PV) and TBA values of the soybean oil (including either 5% or 10% of G. Tournefortii L. seed oil) were determined through an oven test. Moreover, HPLC-UV was employed to qualify and quantify the phenolic compounds. The results indicated that radical scavenging activity of unfractionated oil (TF) was 123.26±0.42 µM; and the methanolic fraction (MF) (85.82±0.58 µM) had a lower scavenging activity than the ethanolic one (EF) (55.09±0.18 µM). However, it was vice versa for non-soluble methanolic (MLF) and ethanolic fractions (ELF) (106.28±0.64 µM and 145.76±0.09 µM, respectively). Luteolin 7-aglycone (0.1878 mg/g oil) and Chlorogenic acid (0.1113 mg/g oil) were determined by HPLC-UV as the most major phenolic compounds of this oil. Total amount of the phenolic compounds was 0.7935 mg/g oil. Finally, a 13day oven test revealed that the highest antioxidant activity was measured during the 8th and 9th day of the test, considering PV and TBA, respectively. This study states that Luteolin 7-aglycone and Chlorogenic acid are among the most abundant phenolic compounds in G. Tournefortii L. seed oil and these compounds are mainly ethanol soluble.