Antimicrobial characteristics of some herbal Oils on Pseudomonas aeruginosa with special reference to their chemical compositions

Pseudomonas aeruginosa is an important opportunistic pathogen causing widespread infections by numerous virulence factors. Increasing resistance to antibiotics makes the Pseudomonas infections treatment further difficult. The purpose of this study was to evaluate antimicrobial characteristics of essential oils from Matricaria chamomilla, Artemisia persica, Zataria multiflora, Myrtus communis, Ruta graveolens, Eucalyptus camaldulensis and Ferula gummosa on Pseudomonas aeruginosa (ATCC 27853).

The selected essential oils were screened against P. aeruginosa using the disc diffusion method. The minimal inhibitory and bactericidal concentrations (MIC and MBC) of the active essential oils were tested using macrodilution method at concentrations ranging from 0.125 to 256 µg/ml. It was found by GC/MS analyses that Z. multiflora, M. communis and E. camaldulensis possess the most potent oils.

Three of the seven essential oils (Z. multiflora, M. communis and E. camaldulensis) were significantly active against P. aeruginosa exhibiting MIC/MBC of 64/128, 64/64 and 64/128 µg/ml, respectively. Gas chromatography mass spectrometry (GC/MS) analysis led to identification of 32, 21 and 22 components in M. communis, E. camaldulensis and Z. multiflora oils, respectively.

With a view to antibacterial activity of some oils against the tested bacterium, their safe antibacterial potentials can therefore be exploited as alternative agents in combating infections of P. aeruginosa origin.