Biochemical studies on some essential oils

Abstract EN

This study was done during 2007 year to investigate antibacterial properties of four essential oils namely, thyme, clove, lemongrass and rosemary against four pathogenic bacteria namely Bacillus subtitles, Micrococcus spp., Mycobacterium phalli and Escherichia coli.

The physical and chemical properties of these oils were determined in order to assess their values and applications.

The chemical composition was determined by gas liquid chromatography and the basic compounds of these oils were identified.

The essential oils were tested for their antimicrobial activity using filter paper disk agar diffusion method Also ; the minimum inhibitory concentration (MIC) of each essential oil was also measured.

The obtained results revealed that all the essential oils under study had antibacterial activity towards all microorganisms under study.

Thyme oil had the highest antibacterial activity followed by clove oil followed by lemongrass oil.

However, rosemary oil was the lowest one.

Gram positive bacteria were very sensitive to all essential oils, such as Bacillus subtilize followed by Micrococcus spp.

Mycobacterium (acid fact bacteria) showed moderate resistance to all essential oils.

On the other hand, E.

coli (Gram-negative bacteria) was more resistance to the essential oils than positive one.

Thyme oil showed a powerful antibacterial towards it followed by clove oil.

However lemongrass oil was the lowest.

MIC of these oils ranged from 0.1 to 2.5mg oil / ml medium.

Therefore, it can use such essential oils as natural preservative agents in food instead of synthetic chemicals.