Natural Oils And Their Antimicrobial Effects On Cuts

Introduction

Wounds are physical injuries that damage the skin or underlying tissues, often caused by accidents, trauma, or surgical procedures, and they can be of two types: open wounds (e.g., cuts) and closed wounds (e.g., bruises). 

Did you know that the history of wound care dates back several centuries? Recorded history suggests that Imhotep, an ancient Egyptian who served under King Djoser and was also a known architect of one of the first pyramids, was one of the earliest physicians. The Ancient Egyptians made significant contributions to wound care by utilising herbal remedies like lint and honey, bandaging, and ointments to facilitate wound healing and prevent infections.¹

Since Imhotep's time, wound care has evolved significantly, integrating advanced medical technologies and research-driven approaches from various disciplines, resulting in more effective and specialised methods in wound treatment and prevention.

This article explores the potential of natural oils as a treatment method to help prevent infections and promote healing in cuts and minor wounds and further investigates how components found in them have antimicrobial effects.

Why is wound care important?

The practice of wound care holds a crucial role in healthcare, involving the effective management and treatment of wounds, be it a minor cut or a more severe burn, to support the healing process while mitigating the risk of infection. 

When you get injured, your body repairs the damaged skin through wound healing first through the formation of a blood clot to stop the bleeding. Immune cells are then transported to the site of the wound through blood vessels, where they release chemicals to trigger the production of new skin tissue. The growth of microbes (tiny living organisms that can only be viewed under a microscope) can affect wound healing, with most wound infections resulting from bacteria.

Bacteria in wounds release tiny chemicals that affect the body's immune cells and blood vessels. These signals also alert other bacteria to infect the body. Immune cells try to fight the bacteria by responding to these signals, but when there are too many bacterial cells and harmful chemicals, it's harder for the immune cells, which further delays wound healing. 

If not cared for, open wounds could lead to severe bacterial infections like gas gangrene and tetanus, which could also potentially lead to long-lasting disabilities, chronic infections in the wounds or bones, and, in some cases, even death.

Natural oils

What are natural oils?

While there are many over-the-counter ointments and creams available for wounds like cuts, there is growing interest in the antimicrobial properties of natural oils as an alternative or complementary treatment. Natural oils are any ‘oil’ that is natural and not synthetically produced. 

These could be vegetable oils, which are fatty oils derived from the flesh of fruits, seeds, vegetables, nuts or even grains, with examples being argan oil, sunflower oil and olive oil. Naturally derived essential oils, obtained from various parts of plants through methods like distillation or mechanical expression, are classified as natural oils, too, and examples include lavender oil and citrus oils. 

What sets essential oils apart from vegetable oils is their volatility. Essential oils are composed of volatile compounds, which means they easily evaporate at room temperature, giving plants their characteristic scents. In contrast, vegetable oils consist of non-volatile compounds called triglycerides, comprising three fatty acids and glycerol. 

Besides plant oils, animal oils are also considered natural oils, and examples are fish oil, emu oil and ostrich oil.²

What natural oils are used in wound healing?

There have been several essential oils that have been reported to help in the healing of wounds and reduce infection in the wound regions. Examples are tea tree oil, clove oil, oregano oil and lavender oil. The Indigenous people of Australia have used tea tree oil for thousands of years for wound healing and skin infections, while the use of lavender oil dates back to ancient Roman and Greek times due to its antimicrobial properties. Clove oil also possesses antibacterial and anti-inflammatory properties, thus being used in herbal medicine to heal wounds like cuts and burns.²

Vegetable oils like argan oil, avocado oil, olive oil, coconut oil and linseed oil have also been shown to have antimicrobial and anti-inflammatory properties that are helpful in wound healing.³

Emu oil, an oil popular with Indigenous Australians, is still used as contemporary medicine for treating wounds like burns and scrapes. Published studies have yet to report that the oil possesses antimicrobial properties, but it has still shown positive effects in anti-inflammation and wound regeneration. Crocodile oil, traditionally used by the Chinese and other Southeast Asians as well as Africans, is known to help with skin rashes and to improve wound healing through processes like skin regeneration and scar reduction.² 

Antimicrobial properties of natural oils

Some key antimicrobial components in natural oils

The table below shows examples of some of the main antimicrobial components found in natural oils, along with examples of natural oils containing these key components.

It is worth noting that some of the examples of components can be classed as different chemical compounds, depending on the context and the specific criteria used by researchers or sources. For example, thymol, eugenol, and carvacrol have been added as examples of phenols. However, they can also be classified as terpenes. 

In fact, terpenes have several sub-categories because of their diverse chemical structures, of which monoterpenes are the majority component found in essential oils. These monoterpenes can have additional -OH (hydroxyl group) added to their structure, thus forming monoterpenoids.⁴ Now, the positioning of the OH group would further determine if the monoterpenoid has additional phenol qualities (if the -OH group is attached to an unsaturated benzene (C6 H6) ring) or alcohol (if the -OH group is attached directly to a saturated carbon) qualities. 

Thymol, eugenol and carvacrol, therefore, fall under monoterpene phenols, while menthol and geraniol are classed as monoterpenoid alcohols.

How natural oils inhibit the growth of microbes

Below, we investigate some of the ways natural oils can inhibit microbial growth:

1. Disruption of cell membranes: Essential oils rich in phenolic components like thymol, carvacrol and eugenol are major drivers of lipid cell membrane disruption, which leads to leakage of cellular contents like proteins and even genetic material (DNA and RNA), with eventual death. The oils have shown positive results in both Gram-positive (bacteria with thick peptidoglycan cell walls) and Gram-negative bacteria (bacteria with thin peptidoglycan cell walls).¹⁰

2. Interference with metabolism: Natural oils can affect microbial metabolism by disrupting vital biochemical processes depending on the concentrations used. For example, phenolic compounds like eugenol and aldehydes like cinnamaldehyde inhibit enzymes like ATPase, an enzyme that helps cells use energy stored in ATP molecules for many cell functions, which can lead to a metabolic standstill.¹¹

3. pH modulation: Certain oils can alter the pH of the environment, creating conditions that are less favourable for microbial growth. For example, essential oils with acidic components like carvacrol can lower the pH of the surrounding environment, making it more acidic, leading to the depletion of ATP molecules and thus inhibiting the growth of some microorganisms.¹²

How to apply natural oils on cuts

Proper preparation and dilution of natural oils

1. Choose the right oil: We first begin by choosing the right oil or a mixture of oils that can reduce pain and inflammation while aiding in wound healing, clearing out microbes and reducing chances of infection.
2. Ensure cleanliness: Before handling any oil, wash hands thoroughly with soap and warm water to prevent contamination.
3. Dilute the oils (if necessary): Many natural oils, especially essential oils, are highly concentrated and should not be applied directly to the skin without diluting them first, though some scenarios like burns, bug bites, or forehead tension could benefit from undiluted usage occasionally. Dilute the oil with a carrier oil, such as olive oil or avocado oil, to a safe and appropriate concentration (Refer to the Essential Oil Dilution Chart for more guidance on appropriate concentrations for different volumes of oils).

    A step-by-step guide to applying natural oils on cuts

1. Clean the Cut: Begin by delicately cleansing the cut with a mild soap and lukewarm water. Gently blot it dry using a clean, sterile fabric. If the cut is too deep, it might also need stitches, but it may be best to have it checked out by a medical specialist in this case.
2. Prepare the Diluted Oil (if needed): If opting for a diluted oil, blend the essential oil with the carrier oil in the correct proportion.
3. Patch Test: Before using any natural oil on the cut, perform a patch test on a small area of your skin to ascertain if any allergic reactions or skin sensitivity arise. Allow 24 hours to ensure there are no adverse responses.
4. Apply the Oil: Use a clean cotton ball or sterile gauze pad to administer a small quantity of the diluted natural oil to the cut. This application of the oil to the skin is topical usage, and it directly benefits the skin. Gently pat the oil onto the wound, ensuring comprehensive coverage.
5. Cover the Cut (if required): Depending on the cut's size and location, consider shielding it with a sterile bandage or dressing to safeguard against contaminants and bacteria.
6. Reapply as Necessary: Reapply the oil and change the bandage (if employed) daily or as dictated by the healing process. Keep a vigilant eye on the wound's progress, and if you observe any signs of infection or worsening symptoms, promptly seek medical attention.

   Precautions

• Cease Use if Irritation Arises: In the event of experiencing redness, itching, or any undesirable skin reactions following oil application, discontinue usage immediately.
• Avoid Sensitive Areas and Eyes: Exercise caution to prevent oil contact with your eyes or sensitive body regions, as it may induce discomfort.
• Secure Oils Away from Children: Given that natural oils can be harmful if ingested, store them in a location inaccessible to children and pets.
• Seek Medical Assistance for Severe Cuts: For deep or serious cuts or if symptoms of infection, such as the presence of pus, heightened redness, or fever manifest, promptly seek professional medical attention.

Bear in mind that although natural oils can have advantageous properties in wound care, they should not substitute expert medical guidance or treatment for severe injuries. When in doubt, consult a healthcare practitioner for counsel on wound care and suitable remedies.

Summary

Wound care has a rich history dating back centuries, with ancient remedies ranging from herbal treatments to incantations. Today, wound care integrates advanced medical technologies and natural remedies, including essential oils, vegetable oils, and animal oils. These natural oils offer antimicrobial properties and can aid in wound healing and infection prevention. Components in these oils, such as phenols, terpenes, and fatty acids, disrupt microbial cell membranes, interfere with metabolism, and modulate pH, hindering microbial growth. Proper application involves cleaning the wound, diluting oils if necessary, and applying them with caution. While natural oils can be beneficial, they should complement, not replace, medical guidance for severe wounds.