In Vitro Antibacterial and Antibiofilm Activity of Lippia alba Essential Oil, Citral, and Carvone against Staphylococcus aureus.

Emanuela Mesquita Porfírio,Mário Geraldo De Carvalho,Geovany Amorim Gomes,Francisco Eduardo Aragão Catunda Júnior,Hider Machado Melo,Renata Albuquerque Costa,Theodora Thays Arruda Cavalcante,Antônio Matheus Gomes Pereira

doi:10.1155/2017/4962707

Abstract

In vitro antimicrobial and antibiofilm activities of the Lippia alba essential oil and its major components (citral and carvone) against Staphylococcus aureus were investigated. Essential oils (LA1EO, LA2EO, and LA3EO) were extracted from the aerial parts of three L. alba specimens by hydrodistillation and analyzed by gas chromatography coupled to a mass spectrometer. Minimum Inhibitory Concentrations (MIC) and Minimum Bacterial Concentration (MBC) were determined by the microdilution method. For the antibiofilm assays, the biomass formation in the biofilm was evaluated by the microtiter-plate technique with the crystal violet (CV) assay and the viability of the bacterial cells was analyzed. All oils and their major components presented antibacterial activity, and the lowest MIC and MBC values were 0.5 mg mL−1 when LA1EO and citral were used. Potential inhibition (100%) of S. aureus biofilm formation at the concentration of 0.5 mg mL−1 of all EOs was observed. However, the elimination of biofilm cells was confirmed at concentrations of 1 mg mL−1, 2 mg mL−1, 2 mg mL−1, and 0.5 mg mL−1 for LA1EO, LA2EO, LA3EO, and citral, respectively. The results obtained in the present research point to the promising antibacterial and antibiofilm potential of L. alba EOs against S. aureus, a species of recognized clinical interest.

Highlights

Antimicrobial resistance in bacterial pathogens is a public health problem worldwide and is associated with high morbidity and mortality, jeopardizing the efficacy of antibiotics
Natural products extracted from plants are identified as an alternative for the discovery of new active antimicrobial agents through empirical knowledge regarding the use of medicinal plants [10]
The results of the LA1EO, LA2EO, and LA3EO analyses are described in Table 1 and Figure 1

Summary

Introduction

Antimicrobial resistance in bacterial pathogens is a public health problem worldwide and is associated with high morbidity and mortality, jeopardizing the efficacy of antibiotics. The present study aims to evaluate the antibacterial and antibiofilm activity of essential oils of three L. alba chemotypes and of their major compounds (citral and carvone) against S. aureus. The test substances (LA1EO, LA2EO, LA3EO, citral, and carvone) were tested at the concentrations of 4, 2, 1, 0.5, 0.25, 0.125, and 0.062 mg mL−1.

Results

Conclusion