Antibacterial activities of the crude ethanol extracts of medicinal plants against Listeria monocytogenes and some other pathogenic strains

Searches for substances with antimicrobial activity are frequent and medicinal plants have been considered interesting by some researchers since they are frequently used in popular medicine as remedies for many infectious diseases. The aim of this study was to verify the antibacterial effect of ethanol extracts of 13 plants (Artemisia Herba Alba, Lavandula officinalis L., Matricaria Chamomilla, Eugenia caryophylata , Cistus salvifolius, Mentha suaveolens subsp. Timija, Thymus serpyllum L.,Lippia citriodora, Cinnamomum Zeylanicum, Rosa centifolia, Thymus vulgaris L, Rosmarinus officinalis and Pelargonium graveolens) against Listeria monocytogenes and other pathogenic strains. These plants are used more for their therapeutic effects in the aromatization of the traditionally fermented dairy products. For this purpose, the agar well diffusion method was the antimicrobial susceptibility performed test. The major components of extracts tested were identified by gas chromatography coupled with mass spectrometry (GC/MS) analysis. The obtained results revealed in vitro anti-Listeria monocytogenes activities of all the extracts. Also, the extracts of clove, mint timija, cinnamon, cistus,rose, thyme, wild thyme, artemisia, rosemary, geranium and camomile presented in this order promises inhibitory capacity with MIC value between 0.25 mg/mL for clove extract and 6.75 mg/mL for camomile extract. On the other hand, the antimicrobial activity was mainly a function of their chemical composition, in particular in the nature of their major volatile compounds. This study thus confirmed the possibility of using these plants or some of their components in food systems to prevent the growthof foodborne bacteria and to extend the shelf-life of processed foods