Overview: The Antibacterial Activity of Essential Oil

The Essential Oil from Several Types of Citrus is Highly Toxic to P. acnes Bacteria

There are an incredible diversity of essential oils and other plant extracts available on the market today.  This selection provides a plethora of options for both professional and casual practitioners of naturopathic and homeopathic medicine.

Much of what makes up an essential oil are molecules which are part of a plant’s natural defense system.  These molecules have been designed by millions of years of evolution to protect the plant against potential enemies.

Some components of essential oil have antibacterial, anti-viral and anti-fungal activity.  Other components in the essential oil are designed to prevent predation by insects and other animals.  Some essential oils may even be toxic to other plants, and are designed to fend off competing plants.

In the last ten years, a great deal of work has been done to characterize the antibacterial activity of many essential oils.  Using this knowledge can help you make better decisions when designing effective naturopathic treatments for acne.

The Antibacterial Activity of an Essential Oil Depends on the Species of Bacteria

This Chart Shows the Toxicity of Many Different Essential Oils on 5 Clinical Strains of P. acnes Bacteria – Lower Numbers Indicate Higher Antibacterial Activity. The Most Effective Essential Oils are Highlighted in Red ((Luangnarumitchai)

Some essential oils are highly toxic to certain species of bacteria, but are harmless to others.  While some essential oils are effective against a broad spectrum of different bacteria, others are only useful against very specific types of bacteria.

When designing an effective naturopathic acne treatment it is important to be aware of these differences.  To better improve the design of acne treatments, we have compiled the research data to identify which essential oils are likely to be most effective.

For an essential oil to be effective against acne, it is important that it be active against Propionibacterium acnes, the primary bacteria behind acne vulgaris. Many essential oils also have anti-inflammatory properties which may help in the treatment of acne symptoms.

What Essential Oils are Effective Against Propionibacterium acnes Bacteria?

The research indicates that there are many types of essential oil that are active against P. acnes bacteria.  Tea tree oil is one of the most popular essential oil, and the research shows that it is indeed toxic to P. acnes bacteria, although not as much as some other treatments.  Thyme, clove and cinnamon essential oil have broad spectrum antibacterials, and are effective against P. acnes as well.  Unfortunately, these extracts can also be fairly irritating to the skin of many people, particularly at higher concentrations.  Interestingly, a wide range of citrus oils (lemon, lime and orange oil) were highly toxic to P. acnes bacteria.  The research also indicates that lemongrass essential oil effectively kills P. acnes bacteria.

Antibacterial Activity of Essential Oil Against Other Bacterial and Fungal Infections

This Chart Indicates the Minimum Concentration of Essential Oil Necessary to Inhibit Bacterial Growth for Many Different Types of Essential Oil and Bacteria – Highly Active Essential Oils are Highlighted in Red (Hammer)

There have been several studies which examine the ability of different essential oils to inhibit or kill infectious bacteria and fungi. This may be useful to acne sufferers because other bacteria, like Staphylococcus or Streptococcus, may also cause skin infections.

No matter what kind of application you have in mind, from naturopathic medicine to designing a natural disinfectant, understanding the antimicrobial properties of different essential oils is a critical first step.

To help improve the understanding of these properties, we have included additional comprehensive information about essential oils and their antimicrobial activities.  Below is a chart that shows the results of one such study that assayed many common essential oils.

Additional Research Results

This Chart Shows the Effectiveness of 10 Essential Oils Against P. acnes Bacteria – The Most Effective Oils are Highlighted in Red (Zu)
Antimicrobial Activity of 21 Essential Oils Against 3 Types of Bacteria – The Most Effective Oils are Highlighted in Red (Prabuseenivasan)

Additional Online Resources

Plant Profiler

References and Sources

Activities of Ten Essential Oils towards Propionibacterium acnes and PC-3, A-549 and MCF-7 Cancer Cells.
Zu, et al. 2010.
Antimicrobial Activity of Essential Oils Against Five Strains of Propionibacterium acnes.
Luangnarumitchai, et al. 2007.
Antimicrobial activity of essential oils and other plant extracts.
Hammer, et al. 1999.
Antioxidant Activities and Volatile Constituents of Various Essential Oils.
Wei, et al. 2007.

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