Study of the Inhibitory Effect of Thymus vulgaris and Eucalyptus camaldulensis on In vitro Growth of Listeria monocytogenes

Abstract

    The antibacterial activity of the Thymus vulgaris and Eucalyptus camaldulensis was studied against Listeria monocytogenes . The inhibiting activity was evaluated by the agar well diffusion method. Results showed that the extracts of both tested plants demonstrated antimicrobial activity against the tested organism but the efficiency of the extracts was significantly affected by the solvent used in the extraction as well as plant species and the concentration. The aqueous extracts appeared to be the highly effective extracts against the tested organism ,it exhibited an inhibition zone 16 mm-24 mm for thyme and 15 mm-24 mm for eucalyptus in comparison with 21mm and23 mm for ampicillin and ciprofloxacin respectively .The alcoholic extract of thyme had no antibacterial activity in concentration of 25 and 50 mg /ml. The results of this study suggest that the antilisterial properties of these plants may be further investigated to explore the possibility of using them in the treatment of listerial infection.