Essential Oils in Antimicrobial Strategies

Essential oils are complex mixtures of volatile plant‐derived compounds that exhibit broad‐spectrum antimicrobial activity against bacteria, fungi and viruses. Their principal mechanisms include disruption of microbial membranes, interference with intracellular targets and inhibition of cell-to-cell communication pathways such as quorum sensing. In addition to directly reducing planktonic cell viability, essential oils can prevent and dismantle biofilms—structured communities of microorganisms encased in an extracellular matrix that confer enhanced resistance to conventional antimicrobials. Synergistic combinations of oils or their constituents with antibiotics, as well as advanced formulations such as encapsulation and hurdle technology, seek to overcome challenges of volatility, solubility and standardisation. Applications span food safety (surface sanitisation, preservative additives), medical devices (coatings to prevent catheter-associated infections), chronic wound dressings and inhalable therapeutics. Continued research aims to optimise delivery systems, define active constituents and ensure safety and efficacy for global antimicrobial stewardship.

Research from Nature Portfolio

A recent study explored the antibacterial and antibiofilm potential of ethanolic extracts from four medicinal plants—Cinnamon, Chamomile, Marigold and Sage—against common foodborne pathogens in dairy processing. The extracts exhibited zone‐of‐inhibition diameters ranging from 12 to 26.5 mm and achieved biofilm reduction up to 99% for Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Salmonella Typhimurium. A mixture of Chamomile, Sage and Cinnamon extracts was optimised for maximal antibiofilm activity on stainless steel surfaces mimicking milk tanks. Gas chromatography–mass spectrometry identified key compounds, the most abundant being a phenylpropenal derivative. This mixture showed no cytotoxicity up to 500 µg ml⁻¹ and, when incorporated into soft cheese, was well accepted by sensory panels, illustrating translational promise for food safety interventions.

Essential Oils in Antimicrobial Strategies publication trend

The graph below shows the total number of articles in essential oils in antimicrobial strategies across all publications each year (not limited to Nature Index journals).

Technical terms

Biofilm: A structured community of microbial cells enclosed in a self-produced polymeric matrix attached to a surface.

Minimum inhibitory concentration (MIC): The lowest concentration of an antimicrobial agent that prevents visible growth of a microorganism.

Quorum sensing: A cell‐density‐dependent communication mechanism by which bacteria coordinate gene expression, including virulence and biofilm formation.

Volatile organic compound: A molecule with sufficient vapour pressure under normal conditions to evaporate and exert antimicrobial effects in the gas phase.

Encapsulation: A formulation technique in which active compounds are enclosed within carrier materials (e.g., liposomes, polymers) to improve stability, solubility and controlled release.

References

1. Effect of Essential Oils of Apiaceae, Lamiaceae, Lauraceae, Myrtaceae, and Rutaceae Family Plants on Growth, Biofilm Formation, and Quorum Sensing in Chromobacterium violaceum, Pseudomonas aeruginosa, and Enterococcus faecalis. Microorganisms (2023).
2. Elimination of detached Listeria monocytogenes from the biofilm on stainless steel surfaces during milk and cheese processing using natural plant extracts. Scientific Reports (2024).
3. Essential oils and their active components applied as: free, encapsulated and in hurdle technology to fight microbial contaminations. A review. Heliyon (2022).