Antimicrobial activities of protenic extracts of Allium roseum L., a wild edible species in North Africa

This work was carried out on Allium roseum L., a North African endemic species, growing in the South-East of Tunisia and used as a vegetable, spice or herbal remedy in traditional medicine. Three protocols of extraction (Tris HCl buffer, phosphate buffer and sulphuric acid) were used in order to extract proteins from four different organs of this species (flowers, bulbs, leaves and seeds). Tris HCl buffer extract showed the highest content of A. roseum protein. Leaves had the highest protein content and seed had the highest diversified molecular weight varying from 10 to 50 kDa comparatively to the other organs. Antimicrobial activities of different protein extracts were tested by disc diffusion and well diffusion and evaluated by the determination of minimum inhibitory concentration (CMI) and minimum bactericidal concentration (MBC). Antimicrobial activities of the extracts against ten tested microbial strains differed depending on the extraction method and plant material used. The determination of CMI and CMB relieved a very significant antimicrobial activity to some strains such as C. albicans and E. coli. Extracts selected for highest antimicrobial activity were tested for sensitivity to heat and proteases. Tested extracts were thermolabile and their activities were sensitive to several proteases including α-chymotrypsine, pepsin and trypsin. Results suggest the potential use of the plant as condiment and preservative in the food industry.