Abstract

Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis of the isolated essential oils obtained by steam distillation from the flowers, leaves, and stems of two plants, known to have medicinal activity, Achillea pachycephala Rech.f. andAchillea santolina L., collected from Khorasan, Northeast of Iran, as well as constituents obtained by solvent (hexane-ether and methanol) extractions of the aerial parts, resulted in the identification of 46 to 60 constituents (95.4 to 98.8% of the total oil and extracts) and 48 to 59 constituents (95.9 to 98.0% of the total oil and extracts), respectively. The hydrodistilled oil of three parts and the solvent extracts of A. pachycephala contain camphene, sabinene, 1, 8-cineole, camphor, borneol, terpinen-4-ol and β-caryophyllene as major constituents. In essential oils and extracts of A. santolina, 1, 8-cineole, camphor, terpinene-4-ol, fragranol, fragranyl acetate, α-terpinyl acetate, caryophyllene oxide, α-muurolol and some alkanes, alkanoic acids and esters were principle components. In vitroantimicrobial activity of essential oil of three parts and crude extracts (hexane-ether and methanol extract) of A. pachycephala Rech.f. and A. santolina L. were investigated by disc diffusion method and the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) determination. The studied samples were active against gram positive and gram negative bacteria. The maximum antimicrobial activities of both plants were shown by the essential oils and the hexane-ether extracts, as compared to methanolic extracts. Both oils and extracts exhibited higher activities against the gram negative tested bacterial strains.

Key words: Achillea, essential oil, solvent extract, antimicrobial activity.