This study reports for the first time, the chemical composition, antibacterial and antifungal activities of the essential oil extracted by hydrodistillation from the bulbs of Allium roseum L. var. grandiflorum Briq. subvar. typicum Regel. In total, 25 compounds, representing 86.5% of the total oil composition, were identified by GC and GC/MS analyses. Sulfurous compounds were detected in appreciable amounts (68.8%) for the first time in the bulbs essential oil. They were acyclic and cyclic compounds (54.0 and 14.8%, respectively). The main compounds were diallyl trisulfide (15.7%), allyl methyl trisulfide (14.1%) and cis-3,5-diethyl-1,2,4-trithiolane (11.0%). No sulfurous compounds was present at lower amounts (17.7%) particularly dominated by aliphatic compounds (13.8%), from which the n-hexadecane (25; 4.7%) was identified as the main. The antibacterial activity was evaluated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus faecalis and Proteus mirabilis. The antifungal activity was assessed against Botrytis cinerea, Alternaria solani, Pythium ultimum, Fusarium oxysporum and Fusarium solani. The tested oil exhibit significant antibacterial activity against Gram-positive strains especially towards Staphylococcus aureus with a minimum inhibitory concentration and a minimum bactericidal concentration of 0.31 mg/ml each and inhibited the growth of almost fungi especially Botrytis cinerea (71.66%). This study showed that the essential oil of Allium roseum var. grandiflorum subvar. typicum bulbs contains chemical compounds with good potential for application in natural health products.

Keywords: Allium roseum L., antimicrobial activity, antifungal activity, essential oil, GC/MS, sulfurous compounds.