Essential Oils of Aromatic Plants with Antibacterial, Anti-Biofilm and Anti-Quorum Sensing Activities against Pathogenic Bacteria

Abstract

Both the ability of bacteria to form biofilms and communicate through quorum sensing allows them to develop different survival or virulence traits that lead to increased bacterial resistance against conventional antibiotic therapy. Here, seventeen essential oils (EOs) were investigated for the antimicrobial, antibiofilm, and anti-quorum sensing activities on Escherichia. coli O157:H7, Escherichia coli O33, and Staphylococcus epidermidis ATCC 12228. All essential oils were isolated from plant material by using hydrodistillation and analyzed by GC-MS. The antimicrobial activity was performed by using the microdilution technique. Subinhibitory concentrations of each EO were assayed for biofilm inhibition in both bacterial strains. Quantification of violacein in Chromobacterium violaceum CV026 was performed for the anti-quorum sensing activity. The cytotoxicity activity of the EOs was evaluated on Vero cell line by using MTT method. Thymol-carvacrol-chemotype (I and II) oils from Lippia origanoides and Thymus vulgaris oil exhibited the higher antimicrobial activity with MIC values of 0.37–0.75 mg/mL. In addition, these EOs strongly inhibited the biofilm formation and violacein (QS) production in a concentration-dependent manner, highlighting thymol-carvacrol-chemotype (II) oil as the best candidate for further studies in antibiotic design and development against bacterial resistance.

Thymus vulgaris L. Essential Oil Solid Formulation: Chemical Profile and Spasmolytic and Antimicrobial Effects

“…The scientific community is in agreement that the actions of these natural phytocomplexes depend not only on the compounds present in greater quantities but on the chemotype. Indeed, it is possible to find very powerful actions [ 42 , 43 ] but also phytocomplexes with much lower antimicrobial action [ 44 , 45 ]. The Thymus oil used contains predominantly phenolic monoterpenes ( Table 1 ) and maintains its antibacterial action even in the solid form by selectively acting on pathogenic bacteria ( Table 3 ).…”

Antioxidant, Antihypertensive and Antimicrobial Properties of Phenolic Compounds Obtained from Native Plants by Different Extraction Methods

“…In addition, recent studies have documented the antibacterial effects of phenol-rich extracts commonly found in plants. These studies have highlighted the use of phenolic compounds to control pathogenic bacteria, including those with a commercial antibiotic resistance profile [ 18 , 19 ]. The antibacterial effects of phenolic compounds have also been primarily associated with the presence of hydroxyl groups in their molecules.…”

Superparamagnetic Iron Oxide Nanoparticles and Essential Oils: A New Tool for Biological Applications

“…Chelating agents, peptide antibiotics, lantibiotics, synthetic chemical compounds, and herbal active compounds are some examples of compounds that have been tested [ 145 , 146 ]. Within the plant-origin compounds, EOs were proved to be able to prevent the formation of biofilms [ 147 , 148 , 149 ]. The ability of EOs to inhibit microbial adherence and further biofilm development is associated by their capacity to disrupt the quorum sensing system (QS) [ 148 , 150 , 151 , 152 , 153 ].…”

“…Within the plant-origin compounds, EOs were proved to be able to prevent the formation of biofilms [ 147 , 148 , 149 ]. The ability of EOs to inhibit microbial adherence and further biofilm development is associated by their capacity to disrupt the quorum sensing system (QS) [ 148 , 150 , 151 , 152 , 153 ]. QS is a largely distributed cell–cell communication process that has been identified not only in bacteria, but also in fungi, protozoa, and recently in bacteriophages [ 154 , 155 , 156 , 157 , 158 ].…”