ORIGINAL ARTICLE The article was published by Academy of Chemistry of Globe Publications www.acgpubs.org/RNP © Published 03/19/2014 EISSN: 1307-6167 Rec. Nat. Prod. 8:2 (2014) 110-120 Chemical Composition of the Essential Oils of Three Thymus Taxa from Turkey with Antimicrobial and Antioxidant Activities F. Zehra Küçükbay 1* , Ebru Kuyumcu 1 , Selma Çelen 2 , Ayşe Dilek Azaz 2 and Turan Arabacı 3 1 İnönü University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, Division of Analytical Chemistry, 44280 Malatya, Türkiye 2 Balikesir University Faculty of Science and Arts, Department of Biology, 10100 Balıkesir, Türkiye 3 İnönü University, Faculty of Science and Arts, Department of Biology, 44280 Malatya, Türkiye (Received October 11, 2011; Revised January 29, 2013; Accepted September 02, 2013) Abstract: GC-MS analysis of the essential oils from aerial parts of Thymus migricus Klokov & Des.-Shost, Thymus fallax Fisch. & Mey. and Thymus pubescens Boiss. & Kotschy ex Celak var. pubescens resulted in the identification of 26, 35 and 53 constituents, respectively. The major components in the essential oil of T. migricus were found to be α-terpineol (30.6%), thymol (20.7%) and α-terpinyl acetate (14.9%) while in the essentiol oil of T. fallax cis-carveol (29.6%) and α-terpineol (10.8%). Carvacrol was a dominant compound with a percentage 66.1% of the essential oil of T. pubescens var. pubescens. The data obtained indicate that the essential oils of Thymus species generally exhibit some bacteriostatic activity. The antioxidant activity of the tested essential oils were found to be slightly lower than butylatedhydroxyanisole (BHA). Keywords: Thymus migricus; Thymus fallax; Thymus pubescens; antimicrobial activity; antioxidant activity. © 2014 ACG Publications. All rights reserved. 1. Introduction Herbs/plants are the oldest friends of mankind. They have been employed in conventional medicine since ancient times, particularly due to their antimicrobial activity, and their medicinal properties have consequently been the object of frequent scientific study [1, 2]. According to the world health organization (WHO), about three-quarters of the world population rely upon traditional remedies (herbs/plants) for their health care [3]. In recent decades, the essential oils and various extracts of plant species have become popular as they have been the sources of natural products. With the increasing acceptance of herbal medicine as an alternative form of health care, the screening of medicinal plants for effective compounds is becoming increasingly important [4]. Essential oils are natural, complex, multi-component systems composed mainly of terpenes in addition to some other non-terpene components [1]. Essential oils may be found in all of the aromatic plant species organs, serving important roles such as the protection of the plant against microorganisms, insects, and herbivorous animals or the attraction of insects responsible for the dispersion of pollens and seeds [5]. Essential oils of many plant species are known to have antimicrobial activity [6], and attempts to characterize their bioactive principles have gained * Corresponding author: E-Mail: zkucukbay@inonu.edu.tr; Phone:+90-422-3411071