Antimicrobial activity of Cinnamomum zeylanicum essential oil against colistin-resistant gram-negative bacteria.

In the current study, we evaluated the antimicrobial activity of Cinnamomum zeylanicum Blume essential oil (Cinn-EO) against a group of thirteen clinical colistin-resistant Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The GCMS analysis showed that cinnamaldehyde was the major compound (94.29%) of the Cinn-EO. The diameter of the inhibition zone by Cinn-EO varied from 24 to 37 mm. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranged between 0.625 and 5 mg/mL. Interestingly, the MBC/MIC was equal to 1 for most tested bacterial strains, indicating an advanced bactericidal effect of Cinn-EO against colistin-resistant Gram-negative bacteria. The absorption, distribution, metabolism, elimination, and toxicity (ADMET) prediction showed good pharmacokinetic properties of the tested cinnamaldehyde. The results suggest that cinnamaldehyde could be a potential alternative to treat infection caused by colistin-resistant Gram-negative bacteria.