Chemical Composition and Antibacterial Effect of Medicinal Plants against Some Food-Borne Pathogen

Background: Pulicaria gnaphalodes, Ducrosia anethifolia, Trachyspermum copticum, Foeniculum vulgare Mill and Majorana hortensis Minch are widely used as herbal plants in traditional medicine and they have been reported to have a variety of therapeutic effects. This study was carried out to evaluate the antimicrobial effects of essential oils (EOs) extracted from these medicinal herbs against six species of food-borne microorganisms. Materials and Methods: The EOs were analyzed by gas chromatography mass spectrometry (GC/MS). The detection of inhibitory effect of the EOs on the tested bacteria was carried out by agar disk-diffusion method and then MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) of the EOs against six bacteria were determined. Results: The analysis of the components of the essential oils (EOs) extracted by gas chromatography spectrometry allowed the identification of 63 compounds of the five tested EOs. All of these five tested EOs indicated an antimicrobial effect against strains of Bacillus sp and Listeria Monocytogenes ATCC1297. Essential oils from T. copticum, M. hortensis and F. vulgare possessed a wide spectrum of antibacterial activity against the growth of the six bacteria with zone diameter of inhibition (ZDI) between 14-32 mm, depending on the susceptibility of the tested organism. Conclusion: Antibacterial efficacy shown by these plants provides a scientific basis and thus validates their use as medicinal remedies. Isolation and purification of different phytochemicals may further yield significant antibacterial agents.