Identification of the constituents of Achillea santolina essential oil and evaluation of the anti-microbial effects of its extract and essential oil.

Background: Some plant extracts, including species of Santolina have antibacterial effects and they can be used as antimicrobial agents in treatment of infections. Hence, the aim of this study was to evaluate the compounds of essential oil and the anti-microbial properties of its essential oil and extract. Materials and Methods: In this experimental study, yarrow plant in late spring was collected from Sistan region in 2008. The compounds of the essential oil were analyzed by GC/MS. In this study, the minimum inhibitory concentration (MIC) and diameter of inhibition zone of growth for the standard strains of Staphylococcus aureus, E.coli, P.aeruginosa, and Candida.albicans were determined through disk diffusion and agar-well diffusion methods and dilution in the liquid medium, respectively. Results: Camphor was the major compound of the essential oil. The standard strains of Staphylococcus aureus presented the greatest sensitivity to the stem extract and leaf extract in MIC> 0.573 and MBC> 1.146, respectively and to the flower extract in MBC> 1.663 and MIC> 0.831, respectively. In addition, it presented an intermediate sensitivity to standard strains E.coli with MBC> 2.293 and MIC> 1.146, respectively to the stem and leaf extract and MBC> 6.650 and MIC> 3.325 respectively to the flower extract. However, the standard strains of Candida albicans and P.aeruginosa did not show a significant sensitivity to the extracts. Also, the essential oil of this plant in comparison with the extracts did not have any significant antimicrobial effects. Conclusion: The plant extracts, especially stem and leaf possess anti-bacterial effects. But further investigations are needed for determining its exact mechanism. [ABSTRACT FROM AUTHOR]