Synergistic Effect of Zataria multiflora Boiss. and Bunium persicum (Boiss.) B. Fedtsch. Essential Oils on Linseed Oil Oxidative Stability

We studied the antioxidant activities of the essential oils of Zataria multiflora Boiss. (ZEO) and Bunium persicum (Boiss.) B. Fedtsch (BEO) in mixed form on linseed oil using (DPPH•), (ABTS•+), H2O2 scavenging, and reducing power assays. After calculation of IC50 for ZEO and BEO separately, interactions of the essential oils were investigated at the form of mixture and the results were given in isobologram. The interactions between antioxidant effects of ZEO, BEO, TBHQ, and α-tocopherol; and isobologram results showed synergistic effect for DPPH• except for BEO with TBHQ and α-tocopherol (1:1) and for ABTS•+ in ZEO with TBHQ (1:1). However, we could not find any synergistic effect for H2O2 scavenging and reducing power assays in any of the interactions. Statistical results showed that the best antioxidant levels of reductive oxidation were 600 ppm for ZEO and BEO, and 20 ppm for TBHQ in mixed form in linseed oil.