Identification of Curcuma longa essential oil compounds and evaluation of its antibacterial effect on some food-poisoning bacteria " in vitro"

The aim of this study was to investigate the chemical composition and antibacterial effects Curcuma longa essential oil “in vitro”. The Curcuma longa essential oil was extracted through the hydrodistillation method. Its components were identified through Gas Chromatography/Mass Spectrometry (GC/MS). Antibacterial effects of Curcuma longa on pathogenic bacteria such as Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa using Disk Diffusion and Well Diffusion Agar methods. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using broth Microdilution method. 27 components were identified in Curcuma longa essential oil. The principle compounds of the essential oil included β-Turmerone (34/42%), α- Tumerone (11/4%), Sesquiphellandrene (10/61%), Zingiberene (9/21%), Tumerone (8/51%) and trans- Caryophyllene (7/86%). Findings showed antibacterial properties of Curcuma longa essential oil. Curcuma longa acted against S. pyogenes with diameters of the inhibition zones of 14 mm. MIC of Curcuma longa essential oil for Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa were 1/8, 1/16, 1/4 and 1, respectively. The results showed that gram-positive bacteria are more sensitive compared with gram-negatives bacteria. This phenomenon is due to the structure and the nature and active compounds of Curcuma longa essential oil.