Composition and resistant modulatory activities of three solvents extracts of lemongrass (Cymbopogon citratus) on methicillin-resistant Staphylococcus aureus (MRSA) determined by GC/MS and HPLC-UV analysis
An evaluation of the antimicrobial resistance modulatory effects of three extractable fractions of lemongrass (Cymbopogon citratus): aqueous and ethanol extracts, and lemongrass essential oil in combination with selected antibiotics ampicillin, tetracycline, streptomycin, cefloxacin and amoxicillin on methicillin-resistant Staphylococcus aureus (MRSA) was performed. Our study showed that at sub-inhibitory concentrations, lemongrass oil highly potentiated the activities of three antibiotics; amoxicillin, streptomycin and tetracycline (all antibiotics also at sub-inhibitory concentrations). The ethanol extract enhanced the activity of tetracycline and ampicillin, while the aqueous extract only increased the activity of tetracycline against MRSA. The activity of cefloxacin with the extracts was either indifferent or antagonistic. GC/MS analysis of the lemongrass oil showed the prominence of three ions: the two isomers Z (neral) and E (geranial) of citral (3,7-dimethyl-2,6-octadienal) and, the acetate of the E-isomer, geranyl acetate, which together made up 94% of the composition. HPLC-UV (λ 233 nm) analysis of the three extracts confirmed that these compounds were dominant in the lemongrass oil. They were also observed in the ethanol and water extracts but to a lesser extent. Our study confirms the antibacterial properties of the extracts especially, lemongrass oil. It also demonstrates that lemongrass oil potentiates the activities of three antibiotics against the biofilm-forming MRSA. This biocidal, anti-biofilm disruption and antibiotic potentiating abilities is mainly attributable to citral and geranyl acetate, a further evidence of lemongrass oil as a very useful source of phytochemicals, especially citral for the fight against antibiotic resistance. In this report, we freely present the raw GC/MS data of the lemongrass oil (Abaye et al. lemongrass GC/MS data 2022) and the HPLC-UV output of the three fractions. A full article has been accepted for publication in the journal Chemistry & Biodiversity (Wiley).
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Chromatograms and mass spectra are freely available