Lemon Grass Essential Oil does not Modulate Cancer Cells Multidrug Resistance by Citral—Its Dominant and Strongly Antimicrobial Compound

Abstract

With strong antimicrobial properties, citral has been repeatedly reported to be the dominant component of lemongrass essential oil. Here, we report on a comparison of the antimicrobial and anticancer activity of citral and lemongrass essential oil. The lemongrass essential oil was prepared by the vacuum distillation of fresh Cymbopogon leaves, with a yield of 0.5% (w/w). Citral content was measured by gas chromatography/high-resolution mass spectrometry (GC-HRMS) and determined to be 63%. Antimicrobial activity was tested by the broth dilution method, showing strong activity against all tested bacteria and fungi. Citral was up to 100 times more active than the lemongrass essential oil. Similarly, both citral and essential oils inhibited bacterial communication and adhesion during P. aeruginosa and S. aureus biofilm formation; however, the biofilm prevention activity of citral was significantly higher. Both the essential oil and citral disrupted the maturated P. aeruginosa biofilm with the IC50 7.3 ± 0.4 and 0.1 ± 0.01 mL/L, respectively. Although it may seem that the citral is the main biologically active compound of lemongrass essential oil and the accompanying components have instead antagonistic effects, we determined that the lemongrass essential oil-sensitized methicillin-resistant S. aureus (MRSA) and doxorubicin-resistant ovarian carcinoma cells and that this activity was not caused by citral. A 1 mL/L dose of oil-sensitized MRSA to methicillin up to 9.6 times and a dose of 10 µL/L-sensitized ovarian carcinoma to doxorubicin up to 1.8 times. The mode of multidrug resistance modulation could be due to P-glycoprotein efflux pump inhibition. Therefore, the natural mixture of compounds present in the lemongrass essential oil provides beneficial effects and its direct use may be preferred to its use as a template for citral isolation.

The Benefits of Plant Extracts for Human Health

“…Essential oils have promising activity against antibiotic-resistant bacteria and chemotherapeutic-resistant tumors. This was supported by the study of Viktorová et al [13] where lemongrass essential oil and especially citral, the dominant component, proved to have potential antimicrobial and anticancer activity. Additionally, Mitropoulou et al [14] investigated the antimicrobial potential of Sideritis raeseri subps.…”

Ketone- and Cyano-Selenoesters to Overcome Efflux Pump, Quorum-Sensing, and Biofilm-Mediated Resistance

“…Anti-QS activity was monitored by two commercial strains of V. campbellii (ATCC BAA-1118 and ATCC BAA-1119). The first one responds by bioluminescence to AI-1 inducer, the second one to AI-2 inducer [ 35 ]. The effect of compounds on the luminescence generation was evaluated as described previously.…”

Phytochemical Composition and In Vitro Biological Activity of Iris spp. (Iridaceae): A New Source of Bioactive Constituents for the Inhibition of Oral Bacterial Biofilms

“…For single-species biofilms, the method described by [26] was used. For the mixed biofilm, overnight cultures adjusted to 0.5 McFarland turbidity of all species: S. gordonii, V. parvula, F. nucleatum, and A. naeslundii were mixed in the same ratio (1:1:1:1, v/v).…”

“…The production of bioluminescence by two commercial (The American Type Culture Collection, ATCC) strains of Vibrio campbellii-BAA1118 and BAA1119 in the presence or absence of tested extracts was determined for the evaluation of anti-QS according to the previous protocol [26]. Autoinducer Bioassay (AB-A) medium, consisting of NaCl (17.5 g/L), MgSO 4 (12.3 g/L), casamino acids (2 g/L), 10 mM potassium phosphate (pH 7.0), 1 mM L-arginine, and glycerol (10 mL/L) was used for inoculating these two strains and all anti-QS experiments.…”