Essential oil composition and antibacterial activity of different extracts of Allium roseum L., a North African endemic species

Abstract

This study deals with the valorisation of medicinal and aromatic plants of the Tunisian flora, in order to find new bioactive natural products. The essential oil constituents from the flowers of Allium roseum var. odoratissimum , a North African endemic species growing in the south-east of Tunisia, were extracted by hydrodistillation and analysed by GC–MS. The most important compounds were sulphurous compounds (2,4-dimethylthiophene, 2-propenyl methyl disulfide, 1-propenyl methyl disulfide, dimethyl trisulfide, and 3-methyl-thiopropionaldehyde or methional). After an exhaustive literature review dealing with other varieties of the same species, it seems that the variety odoratissimum is the only taxon characterized by trisulfide and methional contents. Methional is of particular importance because it is found at high concentration (17%). The antibacterial activity of seven extracts was evaluated by the diffusion method and by determining the inhibition zone. All extracts exhibited an antibacterial activity at different levels against strains reported as the causal agents of food-borne diseases. Results suggest the potential use of the plant as condiment and preservative in the food industry.