Antibacterial and AntioxidantEffects of the Essential Oil and Extract of Zataria Multiflora Boiss

Abstract

Introduction: In this study, Antibacterial and antioxidant activities of the essential oil and methanolic extract of the endemic plant, Zataria multiflora Boiss. have been studied. Method: The antioxidant potential of the samples was evaluated using two separate methods of inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ammonium thiocyanate systems. Antibacterial activity was determined by using disc diffusion method. Results: The antibacterial test results showed that the essential oil of the plant strongly inhibited the growth of all of the microorganisms studied especially the Gram-negative strains. The polar fraction of methanolic extract showed inhibitory effect on Gram-positive strains, while the non-polar fraction showed similar activity similar to the essential oil but not as strong as that. Essential oil and sub fractions of the methanolic extract were able to reduce the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) with an IC50 of 22.4 ± 1.0 for essential oil and 21.7 ± 1.6 and 16.2 ± 1.6 g/ml respectively for non-polar and polar fractions, which the activity of the latter is almost equal to synthetic antioxidant BHA (18.2±1.9 g/ml). Inhibition values of linoleic oxidation were calculated to be 82.4% and 80.3% for the polar and non-polar fractions respectively. The essential oil showed more inhibitory activity (89.7 ± 2.5) that is similar to the synthetic antioxidants BHA (97.8 ± 2.9) and ascorbic acid (93.2 ± 2.1). The chemical composition of hydrodistilled essential oils of Z. multiflora was analyzed by GC/MS. A total of 25 compounds representing 99.78% of the oil were identified. Thymol (37.59%), carvacrol (33.65%); para cymene (7.72%), gamma terpinene (3.88%) and beta caryophyllene (2.06%) were the main components comprising 84.9% of the oil. Conclusion: The obtained results show that the essential oil and methanolic extract of Z. multiflora possess antioxidant and antibacterial activities, therefore Z. multiflora could be used as a natural preservative ingredient in food and drug industries.