58PHYTOCHEMICAL SCREENING AND ANTI-LISTERIAL ACTIVITY OF ESSENTIAL OIL AND CRUDE EXTRACTS FROM SOME MEDICINAL PLANTS GROWING WILD IN BECHAR (SOUTH WEST OF ALGERIA)The antibacterial effect of essential oil and crude extracts extracted from six aromatic plants (Rosmarinus officinalis L, Matricaria pubescens (Desf.), Artemisia herba-alba Asoo, Rhetinolepis lonadioides COSS, Vitex agnus castus and Juniperus phoenicea) was investigated against Listeria monocytogenes. We wanted to proof an antibacterial activity of those plants with two most commonly used methods: disc diffusion method and br oth dilution method. With the disc diffusion method we have obtained the inhibition zone. Minimal inhibitory concentration (MIC) corresponding at the lowest concentrations, where no visible bacterial growth was recorded, were assumed as values (MIC). Overall, extracts from Matricaria pubescens (Desf.) and Artemisia herba-alba Asoo showed the stronger anti-Listeria activity than the others plants. The diameters of growth inhibition zone ranged from 24 to 31mm (including the diameter of the disc-6 mm) with the highest inhibition zone values observed with ethanolic extract of M. pubescens (Desf.) (31mm). For essential oils obtained from hydrodistillation. The diameters of inhibition zone ranged from 13 to 18mm (including the diameter of the disc -6 mm) with the highest inhibition zone values (18mm) observed with Rhetinolepis lonadioides COSS, Vitex agnus castus and Artemisia herba-alba Asoo. We determined MIC values in the ranges from 0.5 to 2.5 mg/ml for extracts and essential oil in the medium. The MIC values of the ethanolic extract against Listeria monocytogenes was 0.5 mg/ml with M. pubescens (Desf.).aabouhajer@yahoo.frResearch422014Listeria monocytogenes,Medicinal plants,Essential oil,Crude extracts,Antilisterial activity,Phytochemical screeningA Makhloufi,A Bouyahyaoui,N Seddiki,L Benlarbi,L Mebarki,A BoulanouarLaboratory of valorization of vegetal Resource and Food Security in Semi Arid Areas, South West of Algeria, BP 417, University of Bechar, Algeria,Laboratory of valorization of vegetal Resource and Food Security in Semi Arid Areas, South West of Algeria, BP 417, University of Bechar, Algeria,Laboratory of valorization of vegetal Resource and Food Security in Semi Arid Areas, South West of Algeria, BP 417, University of Bechar, Algeria,Laboratory of valorization of vegetal Resource and Food Security in Semi Arid Areas, South West of Algeria, BP 417, University of Bechar, Algeria,Laboratoire des productions, valorisations végétales et microbiennes, Université des sciences et de la technologie d’Oran Mohamed Boudiaf, Algeria,Laboratory of valorization of vegetal Resource and Food Security in Semi Arid Areas, South West of Algeria, BP 417, University of Bechar, Algeria