Synergistic antioxidant activity of three essential oils of Lamiacea family from Morocco

Abstract

Essential oils are increasingly becoming important in the food industry due to their preservative power. The present study was carried out to evaluate the antioxidant effect of three essential oils namely: Thymus leptobotrys, Origanum compactum and Calamintha officinalis. We also investigated the possible synergistic interactions on antioxidant efficacy of those essential oils. Samples were obtained by steam distillation from the aerial parts and tested for their antioxidant activity alone and in mixture quantitatively by the DPPH (2,2-diphenylpicrylhydrazyl) free radical scavenging method at the concentrations of 2, 1, 0.5, 0.25, 0.125mg/ml. The data showed that the oil obtained from Origanum compactum possessed the highest antioxidant activity with an IC50 value of 0.85 mg/ml. The lowest antioxidant potency was observed in Calamintha officinalis essential oil. Also, on the basis of the antioxidant combination index (CI) the essential oils mixture showed synergy when the mixture of Thymus leptobotrys/Calamintha officinalis and Origanum compactum / Calamintha officinalis was used. Whereas, the combination of Thymus leptobotrys and Origanum compactum showed additive effect.