Comparative antimicrobial activity of Cymbopogon citratus essential oil and thiosemicarbazones derived from this oil

Abstract

Introduction: The presence of microbes in our environment is always a permanent public health problem. In this context, research on natural treatment, less expensive and accessible to fight these microbial germs would be beneficial. Methods: During this work, molecules of thiosemicarbazones due to their numerous biological activities were hemi-synthesized in situ in the essential oil of Cymbopogon citratus in order to evaluate their antimicrobial activities. Results: Analysis of the essential oil extracted by hydrodistillation revealed the presence of 72.91% of citral. Citralthiosemicarbazone (CThio) and citral 4-phenyl-3-thiosemicarbazone (CPthio) were hemi-synthesized in this oil with interesting yields of 83% and 91%, respectively. After purification and confirmation of the structures of these molecules, the three substances were tested on eleven strains of microbes. Determination of the inhibition diameters showed that the activity of the essential oil is best in over 80% of strains. However, the largest diameter of inhibition (26 mm) was noted with CPthio against Salmonella typhi R 30951401. The determination of the minimum inhibitory concentrations showed that the oil remains more active with the smallest value of 0.3125 mg / ml against Micrococcus luteus. The lower value of minimum bactericidal concentrations was also obtained with the essential oil against Enterococcus foecalis ATCC 29212. Conclusion: The essential oil of C. citratus remains more active in the majority cases. It could be a great alternative in the fight against bacteria, and the advantage is that it remains a natural substance.