Chemical composition, antibacterial and antioxidant activities of a new chemotype of Tunisian Thymus vulgaris oils growing in Sayada

Author: Belsem Marzouk ¹, Hayet Edziri ¹, Ihsen Haloui ², Manel Issawi ³, Imed Chraief ³, Mahjoub El-Ouni ¹, Nadia Fnina ² and Zohra Marzouk ^4*

Received 21 January 2009, accepted 15 April 2009.

Abstract

Tunisia recently increased research in traditional herbal medicines after observation that they are effective for conditions to which they have traditionally applied. Present study is a scientific approach to re-establish the traditional uses of Tunisian Thymus vulgaris, to describe the chemical composition of its essential oils and to evaluate their antibacterial and antioxidant activities. The essential oils, obtained from fresh and dried leaves and flowers (in bud and in bloom) by hydrodistillation, were analysed by gas chromatography and mass spectrometry. The antimicrobial activity was tested against four reference strains by the dilution method and the antioxidant effect was evaluated. Thirty eight compounds were identified. In all oils, oxygen containing monoterpenes were the most abundant chemical group (from 80.9% in fresh flowers in bud to 88.8% in dried flowers in bloom), especially carvacrol (75.73% and 84.81% respectively). The oils displayed an antimicrobial activity. Escherichia coli and Enterococcus faecalis are the most sensitive, particularly to oils from fresh flowers in bud with the same MIC value of 0.2% and MBC values of 1.6 and 0.4%, respectively. All the extracts decreased significantly the signal of DPPH radicals (up to 98.43%).

Key words: Thymus vulgaris L., essential oils; chemical composition; antibacterial activity, antioxidant activity, Sayada.