Evaluation of the Antibacterial Activity of Essential Oil of Dysphania ambrosioides (L.) Mosyakin and Clemants Against Clinical Multidrug-Resistant Bacteria

Abstract

Background and Objective: The discovery of new antibacterial agents is of high priority particularly given the global threat of bacterial resistance. A potential source to improve the current antibacterial arsenal may be in exploiting natural compounds such as essential oils (EOs). The present in vitro study investigated the chemical composition and the antibacterial activity of EO extracted from Dysphania ambrosioides. Materials and Methods: The EO was obtained by hydrodistillation using a clevenger-type apparatus and analyzed by Gas Chromatographic-Mass Spectrometry (GC-MS). The evaluation of the antibacterial activity was performed by the agar diffusion method and the broth microdilution method on six bacteria. Four clinical multidrug-resistant bacteria encompassing Extended-Spectrum $-Lactamase-Producing Escherichia coli (ESBL-EC ), Carbapenem-Resistant Acinetobacter baumannii (CRAB ), Ceftazidime-Resistant Pseudomonas aeruginosa (CRPA) and Methicillin-Resistant Staphylococcus aureus (MRSA) and two sensitive reference bacterial strains (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213). Results: The EO yield was 0.65%. The chemical analysis revealed the presence of 10 compounds including p-cymene (31.72%), 4-carene (27.34%) and "-cyclogeraniol acetate (16.90%). The EO had antimicrobial activity against all the tested bacteria. The minimum inhibitory concentration (MIC) recorded for E. coli ATCC was 90 and 120 µg mLG1 for S. aureus ATCC 29213, 120 µg mLG1 for CRPA, 140 µg mLG1 for CRAB, 150 µg mLG1 for ESBL-EC and 230 µg mLG1 for MRSA. Conclusion: The EO investigated in this study showed an interesting antibacterial activity against the tested bacteria. This might be due to the diversity of its chemical compounds. Promisingly, current results may have potential applications in the drug discovery process of new antibacterial agents. However, further research is needed to depict the mechanisms involved in this observed antibacterial activity.