Epilobium species have been traditionally used as medicinal plants for centuries. The present work studies the chemical composition and antibacterial activity of the essential oil of Epilobium hirsutum L. from Iran. The essential oil of the aerial parts of the plant was extracted by hydrodistillation method and analyzed by GC and GC/MS. Thirty-two compounds were identified in the essential oil, representing 99.8% of the total oil. The most abundant component was pulegone, constituting 74.6% of the oil. Furthermore, antibacterial activity of the oil was investigated using the disc diffusion method, with determination of minimum inhibitory concentration (MIC), against four bacterial including Staphylococcus aureus, Bacillus cereus, Salmonella enterica and Escherichia coli. The essential oil exhibited in vitro antibacterial activity against all tested bacterial strains. Minimum inhibitory concentrations of the oil on the growth of S. aureus, B. cereus, S. enterica, and E. coli were 3.1, 3.1, 50 and 25%, respectively. Conclusively, E. hirsutum can be considered as an herbal antibacterial agent.
