Tehran University of Medical Sciences Traditional and Integrative Medicine 2476-5104 1 2 2016 03 16 59 65 EN Fatemeh Ghazian Central Laboratory, Barij Essence Pharmaceutical Company, Kashan, Iran Seyede Nargess Sadati Department of Traditional Pharmacy, School of Persian Medicine, Tehran University of Medical Sciences, Tehran, Iran Mahnaz Khanavi Department of Traditional Pharmacy, School of Persian Medicine, Tehran University of Medical Sciences, Tehran, Iran AND Department of Pharmacognosy and Persian Medicine, School of Pharmacy, Pharmacy Research Center, Tehran University of Medical Sciences, Tehran, Iran Leila Mohammad-Taghizadeh Kashani Department of Traditional Medicine, Medicinal Plants Research Center of Barij, Kashan, Iran 2016 03 16 Essential oil obtained from medicinal plants has been shown to have different biological activities and could replace chemical antioxidants to decrease oxidation of toxic chemical constituents and prevent disorders associated with oxidative damages. This study was aimed to evaluate chemical compositions and antioxidant activities of the essential oils obtained from Citrus aurantifolia (lime), Citrus sinensis (orange) peel, and Zataria multiflora aerial parts growing in Iran. The chemical composition and antioxidant activities of essential oils were examined using 2, 2-diphenyl-1- picrylhydrazyl (DPPH) scavenging activity and β-carotene bleaching methods. The results were compared with butylated hydroxyl toluene as a synthetic antioxidant. The chemical compositions of essential oils were analyzed with gas chromatography and mass spectrometry. Limonene (40.33%), β-pinene (9.45%), α-terpineol (10.88%), and γ-terpinolene (8.89%) were identified as the major compounds of the oil from C. aurantifolia peel. The main component in the oil of C. sinensis peel was  limonene (90.492%), and thymol (38.67%), carvacrol  (15.29%), p-cymene (10.23%), and γ-terpinene (9.75%) were the main components in the essential oil obtained from Z. multiflora. Z. multiflora essential oil showed potent antioxidant activity by DPPH (76%) and β-carotene bleaching (73.3%) methods. This study indicated that Z. multiflora essential oil exhibited the highest radical scavenging effect and could be used as an obtainable source of natural antioxidant. https://jtim.tums.ac.ir/index.php/jtim/article/view/24 https://jtim.tums.ac.ir/index.php/jtim/article/download/24/41