Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity

Abstract

The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05). The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01). Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001). The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

Inhibition of Glucosyltransferase Activity and Glucan Production as an Antibiofilm Mechanism of Lemongrass Essential Oil against Escherichia coli O157:H7

“…In addition, C. citratus EO was able to inhibit Staphylococcus aureus and Streptococcus mutans biofilms [11,12]. Previous evidence described the ability of citral and geraniol-like terpenes to traverse the bacterial membrane and interact with vital metabolic enzymes [13]. Previous studies also evidenced the potential of citral to inactivate several enzymes [14,15].…”

Assessment of cytotoxic and antimicrobial activities of two components of Cymbopogon citratus essential oil

“…Additionaly, eight randomly selected clinical isolates of S. mutans obtained from schoolchildren with white spot and cavitated caries lesions from a previous study ( 22 ) were included. For determination of the minimum inhibitory concentration (MIC), agar dilution assays were performed following the methodology given in a previous study ( 15 ). Compounds under study were serially diluted in 2-fold steps and then 1 mL of each dilution was added to 18 mL of brain heart infusion (BHI) agar and mixed thoroughly before pouring.…”

“…In order to avoid the side effects of synthetic products, natural products, such as pure compounds or standardized plant extracts, have provided opportunities as new drugs for control of biofilm formation due to their chemical diversity ( 11 ). In this sense, previous researches have demonstrated the antimicrobial activity of the essential oil Cymbopogon citratus on Streptococcus mutans planktonic cultures ( 12 , 13 ) and S. mutans biofilms ( 14 - 16 ). This essential oil of C. citratus has three main components: alpha citral (geranial), beta citral (neral) and myrcene.…”

Evaluation of pH and chlorine content of a novel herbal sodium hypochlorite for root canal disinfection: An experimental In vitro study

“…[ 20 ] It shows antimicrobial activity against standard and clinical strains of streptococci[ 21 ] and is attributed to the presence of citral compound that inhibits biofilms formation. [ 22 ]…”