title: Chemical composition and antibacterial activity of essential oils from the Tunisian Allium nigrum L.
abstract: The chemical composition of the essential oils of different Allium nigrum L. organs and the antibacterial activity were evaluated. The study is particularly interesting because hitherto there are no reports on the antibacterial screening of this species with specific chemical composition. Therefore, essential oils from different organs (flowers, stems, leaves and bulbs) obtained separately by hydrodistillation were analyzed using gas chromatography-mass spectrometry (GC-MS). The antibacterial activity was evaluated using the disc and microdilution assays. In total, 39 compounds, representing 90.8-96.9 % of the total oil composition, were identified. The major component was hexadecanoic acid (synonym: palmitic acid) in all the A. nigrum organs oils (39.1-77.2 %). We also noted the presence of some sesquiterpenes, mainly germacrene D (12.8 %) in leaves oil) and some aliphatic compounds such as n-octadecane (30.5 %) in bulbs oil. Isopentyl isovalerate, 14-oxy-α-muurolene and germacrene D were identified for the first time in the genus Allium L. All the essential oils exhibited antimicrobial activity, especially against Enterococcus faecalis and Staphylococcus aureus. The oil obtained from the leaves exhibited an interesting antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 62.50 µg/mL against these two latter strains. The findings showed that the studied oils have antibacterial activity, and thus great potential for their application in food preservation and natural health products.
authors.affiliation: Laboratory of Genetic, Biodiversity and Valorisation of Bioressources (LR11ES41), High Institute of Biotechnology of Monastir, Tunisia.
authors.forename: Lamia Sakka
authors.initials: LS
authors.lastname: Rouis-Soussi
authors.affiliation: Laboratory of Genetic, Biodiversity and Valorisation of Bioressources (LR11ES41), High Institute of Biotechnology of Monastir, Tunisia.
authors.forename: Asma El
authors.initials: AE
authors.lastname: Ayeb-Zakhama
authors.affiliation: Laboratory of Transmissible Diseases and Biologically Active Substances, Faculty of Pharmacy of Monastir, Tunisia.
authors.forename: Aouni
authors.initials: A
authors.lastname: Mahjoub
authors.affiliation: Dipartimento di Farmacia, Via Bonanno 33, 56126 Pisa, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Flamini
authors.affiliation: Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity, Team: Medicinal Chemistry and Natural Products, Faculty of Sciences of Monastir, Avenue de l'Environnement, 5000 Monastir, Tunisia.
authors.forename: Hichem Ben
authors.initials: HB
authors.lastname: Jannet
authors.affiliation: Laboratory of Genetic, Biodiversity and Valorisation of Bioressources (LR11ES41), High Institute of Biotechnology of Monastir, Tunisia.
authors.forename: Fethia
authors.initials: F
authors.lastname: Harzallah-Skhiri
keywords: Allium nigrum L.; GC-MS analysis; antibacterial activity; essential oils; organs