Antimicrobial activity and chemical composition of endemic Centaurea cariensis subsp. niveo-tomentosa.

The antimicrobial activity of the n-hexane, chloroform, ethyl acetate and ethyl alcohol extracts of the aerial parts of Centaurea cariensis subsp. niveo-tomentosa was evaluated against microorganisms, including multi-antibiotic resistant bacteria, using the paper disc diffusion method. The chemical composition of the chloroform extract of this plant was determined by gas chromatography and gas chromatography-mass spectrometry. The chloroform extract exhibited significant antibacterial activity for all bacteria tested, which are important pathogens. The major compounds of the chloroform extract were caryophyllene oxide (20.79%), spathulenol (14.73%), beta-eudesmol (9.27%), beta-caryophyllene (6.84%), n-cetylalcohol (6.27%), cubenol (5.23%) and cis-alpha-santalol (4.67%), respectively.