Eucalyptus is a fast-growing plant native to Australia. With long stems, circular leaves, and gum-infused bark, the tree is one of the world’s most widely cultivated plants. The plant’s leaves have been traditionally used for anti-inflammatory, analgesic, and antipyretic (against fever) remedies. They have come handy in relieving the symptoms of respiratory infections like flu, cold, and sinus congestion. The leaves are not easy to digest if consumed whole. Their tea is suitable for consumption, however.
Having around 900 species and subspecies belonging to the Myrtaceae family, the tree is quite popular for its pulp, timber, and essential oil that comes from its leaves. The bioactive constituents found in eucalyptus have antifungal and antibacterial effects and that makes it important to the medical and cosmetic industry.
Eucalyptus essential oil – a pale yellow or colorless liquid – possess wide-range of therapeutic uses and medicinal properties. The oil has a camphoraceous odor with a pungent taste. People also experience a sensation of cold after application or inhalation of this oil. The oil is used in many ointments and medications because of its immense therapeutic properties. The eucalyptus oil’s major constituent 1,8-cineole, also known as eucalyptol, is the major contributor to these properties
Interesting history of eucalyptus oil
Being native to Australia, eucalyptus was first used by the aboriginal folks. They used to call it ‘kino’ and used the plant to heal wounds. The leaves were made into brews to treat colds, body pains, fevers, and sinus congestion. That is why the tree was nicknamed as the ‘Fever Tree’.
The medicinal use of the tree leaves traveled from Australia to England. Legend has it that an English settler accidentally cut his thumb with an ax. His father told him to apply a bandage of bound eucalyptus leaves on the stitched cut. His father had learned this from Aboriginal folk medicine.
At another point in time, a surgeon observed that eucalyptus leaves saved the wound from infection and sped up the healing process. This piece of information disseminated across Australia. Pharmacists started making plans to produce oil commercially. After that, the distillation of leaves began, and then in the 1880s, the surgeons began to use this oil in operations because of its antiseptic activities.
Chemical composition of eucalyptus oil
Main components in most of the Eucalyptus oil varieties include: 1,8 cineole, α-Terpineol, α-pinene, p-Cymene, Sabinene, β-pinene, Camphene, Limonene, Camphor, α-phellandrene, Globulol, Aromadendrene, and Piperitone.
1,8 Cineole: This is the principal constituent of eucalyptus oil and is also known as eucalyptol. It manifests antibacterial, analgesic, anti-inflammatory, antifungal, antispasmodic (the one that suppresses muscle spasms), and antiviral properties. It is known to increase the blood flow and reduce the tension headaches. 1,8 Cineole has also been reported to show toxicity against head lice. Research shows that it reduces stress and can be effective in reducing preoperative anxiety.
Pinene: This compound is known for its antiseptic, bronchodilator, and anti-inflammatory activities. Owing to its expectorant properties, the compound is included in many cough-relieving medications.
α-Terpineol: It exhibits activity against bacteria, fungus, and plays a role in reducing inflammation.
Camphene: It has soothing, antioxidant, and anti-inflammatory properties. It also exhibits anti-congestive activity and is thus effective in relieving the symptoms of cough, sinusitis, migraine, and cold.
Limonene: It exhibits anti-oxidative and anti-inflammatory activities. It helps prevent and treat cancer, bronchitis, and also contributes positively to weight loss. It is used in medications for its various properties.
Sabinene: It has antimicrobial, antioxidant, anti-inflammatory, and antifungal properties. This compound also acts as an antiseptic and anti-ulcer substance.
Camphor: It exhibits antitussive (anti-cough), absorbent, decongestant, anesthetic, anti-inflammatory, and antimicrobial properties. Adequate quantities of camphor along with other medicinal products are used to relieve pain, cold sores, warts, osteoarthritis, hemorrhoids, counterirritant, and anti-itch.
P-Cymene: This compound exhibits antioxidant, antimicrobial, and anti-cancer activities.
Globulol: It has sedative, anesthetic, regenerative, and antioxidant properties.
Aromadendrene: It has antiviral and antibacterial properties. It is used as a disinfectant and is helpful in relieving infections.
Citronellol: It has antifungal, antimicrobial, antispasmodic, antioxidant, anti-inflammatory, and anticonvulsant properties. It is also used as an insect-repellant.
Piperitone: This compound is used as a decongestant.
Medicinal properties of eucalyptus oil
Eucalyptus oil has been used for medicinal purposes for hundreds of years because of its antiseptic, antibacterial, and antifungal nature.
1. Anti-fungal
Research shows that the oil from lemon-scented eucalyptus exhibits fungicidal activity. It inhibits the growth of fungi and tends to exterminate it. It has been known to control the apple gray mold variety of fungus successfully. A study that examined the antifungal activity of eucalyptus in comparison with a fluconazole control showed that eucalyptus proved to be more effective than the aforementioned antifungal medicine.
Another study examined the antifungal activity of eucalyptus and 29 other essential oils against Candida—a fungal infection. It found that among the 18 oils that acted against Candida, eucalyptus was the strongest.
2. Antibacterial
Multiple studies have shown that eucalyptus oil manifests moderate to strong antimicrobial activities. A study evaluated the antibacterial activity of different essential oils against a species of eucalyptus oil. The eucalyptus oil exhibited a relatively stronger antibacterial activity.
Another in vitro study examined the antibacterial and anti-adhesion properties of five essential oils, eucalyptus, lavender, rosemary, manuka, and tea tree. Eucalyptus, manuka, and tea tree completely killed the bacteria in exposure for 30 seconds.
Another study tested the effects of oils from the leaf, stem, and flower of two Eucalyptus species on nine bacterial species. The four of those bacteria showed high sensitivity to the oils, while two of them showed mild vulnerability, and the others showed little to no sensitivity.
3. Antioxidant
The process of infection leads to inflammation that causes the release of free radicals or reactive oxygen species. These free radicals are responsible for cell damage and death. Antioxidants are molecules that prevent free radicals from damaging the cells.
Natural antioxidant molecules are more effective than synthetic molecules. Hence, the natural sources of antioxidants are valued highly. One of such sources is eucalyptus oil. In a study that evaluated the antioxidant activity of eucalyptus oil, it was found that increasing the concentration of this oil augments the radical-scavenging activity.
4. Anti-Inflammatory
Many of the constituents of eucalyptus oil have anti-inflammatory properties. Some researchers found that eucalyptol (the major component of oil) is an inhibitor of inflammatory cytokines. They recommended this component as a long-term treatment of airway inflammation in bronchial asthma.
Another double placebo-controlled trial showed that the anti-inflammatory property of eucalyptol makes it an effective remedy for severe asthma and upper and lower airway diseases.
A few researchers also state that eucalyptol can control mucus secretions. That means it may reduce symptoms of sinusitis, asthma, and chronic obstructive pulmonary disease (COPD).
5. Antiseptic (cleans wounds)
Eucalyptus leaves have been traditionally used as an antiseptic. The aboriginal Australians used those to clean wounds, as they believed eucalyptus prevents infection. Presently, the diluted oil is used on the skin to treat inflammation and accelerate the healing process. Evidence has it that applying eucalyptus oil can help soothe a cut, burn, wound, or abrasion on the skin. The oil has germicidal properties and can be used to relieve insect bites or stings. Multiple studies have proven the antiseptic properties of this essential oil.
However, the oil is not safe for direct application. One should dilute it with water, and its exposure should be less than 3.5 ml. Over-exposure to eucalyptus oil can result in nausea, dizziness, and several other side effects.
6. Empowers immune system
Research shows that several essential oils tend to stimulate immune responses. Eucalyptus oil is one of them, as it has immune-stimulant effects on the cells. Several studies have proven that this oil is capable of activating the innate immune cells and dramatically stimulating their preventive response.
The research offers scientific support to the idea of additional use of eucalyptus extract, apart from its use for antiseptic and anti-inflammatory activities. Some researchers have suggested that the oil can be useful as an adjuvant in infectious disease, pathologies, and after-tumor chemotherapy.
7. Eucalyptus for dry skin
Eucalyptus is believed to have a magical effect on dry skin. There is anecdotal evidence that eucalyptus oil is one of the most effective natural remedies for dry skin. Studies show that this oil can increase the level of ceramide—lipids that are responsible for skin moisture—in the skin cells. It also helps stratum corneum, the skin’s outermost layer, in water retention and barrier function.
One study in people with dry skin linked the increased content of ceramides in the skin cells with the therapeutic effect of eucalyptus oil. Another study examined 34 participants with different skin conditions, i.e., atopic dermatitis, pityriasis capitis, and seborrheic dermatitis for four weeks. The participants were provided with a daily dose of a pseudo-ceramide as well as a lotion containing eucalyptus. The symptoms of the said skin conditions improved prominently in all the subjects. The use of lotion improved skin scaling, erythema, and dryness. The moisture-retention ability of the skin cells enhanced, and itchiness decreased drastically. Eucalyptus oil is, therefore, an effective choice for dry skin.
Eucalyptus oil for skincare
Being an antiseptic, antibacterial, and antioxidant, eucalyptus oil holds many benefits for the skin. Here are the ones most studied:
1. Retains skin’s moisture
Eucalyptus oil promotes the production of ceramides, which ensure moisture retention. One study shows that the topical application of eucalyptus oil improves the overall appearance of skin as well as skin health. It tends to have positive effects on dry, sensitive skin.
2. Helps with premature skin-aging
Premature aging of the skin happens due to the damage caused by free radicals. The antioxidant properties of eucalyptus oil prevent and limit the impact of free radicals. This way, they protect the skin against aging.
3. Helps with acne
The antibacterial properties of eucalyptus oil make it a suitable option for acne. Acne starts because of clogged pores, which are small openings in the skin. The pores clog because of hair follicles and accumulated sebum, an oily substance. The accumulated sebum mixes with dead skin cells and forms a sticky plug. That provides room for bacteria to grow fast. The bacterial activity causes swelling, irritation, and redness.
Applying eucalyptus oil prevents bacterial activity and ultimately relieves acne. The oil can also be helpful in treating blackheads, pimples, and whiteheads.
4. Lightens skin complexion
There is anecdotal evidence that eucalyptus oil can lighten the skin. It has also been known to remove wrinkles and tighten the skin. It also helps lighten the spots from blemishes and dark circles. That is why many skincare products contain eucalyptus oil.
5. Improves skin health
Eucalyptus oil exhibits anti-inflammatory activity. It also promotes blood circulation, which helps improve skin health. It deals with the redness, itchiness, and swelling of the skin as a result of inflammation. Because of these properties, this essential oil helps invigorate and rejuvenate the skin.
Amazing uses of eucalyptus oil to alleviate medical problems
Eucalyptus oil can help alleviate many medical conditions like:
Bronchitis
Limonene, a compound found in eucalyptus, has been known to help ease the symptoms of bronchitis. Moreover, one study found that the major component of eucalyptus oil, i.e., cineol reduces the flare-ups caused by bronchitis.
Gingivitis
Gingivitis is characterized by inflammation of the gums. It occurs when a film of bacteria or plaque starts accumulating on teeth. This condition is non-destructive but can cause poor gum and bone health if left untreated. Because of its anti-inflammatory and antibacterial properties, eucalyptus oil can help improve the condition. A research study showed that chewing gum with 0.4 to 0.6 percent of eucalyptus oil can alleviate the symptoms of gingivitis.
Bad breath
Mint is not the only magic remedy when it comes to bad breath. Eucalyptus oil can also eliminate the germs responsible for unfortunate smell, all thanks to its antibacterial properties, and that is why this oil is an active ingredient in many kinds of toothpaste and mouthwash.
Moreover, eucalyptus oil prevents and even reduces the plaque buildup on the teeth. Plaque buildup can also be a cause of bad breath, and the oil can remove this very reason. A four-week study on plaque formation involved 100 volunteers. The volunteers were provided with a standard toothpaste containing different concentrations of eucalyptus oil, spearmint oil, and chlorhexidine. The eucalyptus oil manifested significantly more inhibition than the other added components.
Headache
Eucalyptus oil is deemed a natural painkiller. It can help alleviate the headache as well. Applying eucalyptus oil to the head can relax the headaches and help to think better.
Lice
Eucalyptus oil is an effective natural remedy for the treatment of head lice. According to a 2017 Australian study, eucalyptus is a safe, easy-to-use, and effective alternative to remove the head lice. The over-the-counter products for life treatment have multiple side effects. Therefore, several researchers are looking if complex plant components can pass as a substitute. They found eucalyptus oil to be suitable in this regard.
Diabetes
Eucalyptus oil is believed to lower blood sugar. Scientific evidence also points to the same conclusion. In 2015, the researchers found that eucalyptus oil increases glucose uptake. Also, it may lead to improved glucose tolerance, lower fasting glucose levels, and reduced insulin resistance.
Another study indicated that eucalyptus oil inhibits the enzymes responsible for type 2 diabetes. However, the use of eucalyptus alongside medications for diabetes can lower blood sugar too much. One should monitor blood sugar levels closely while consuming both. It is best to consult your doctor in this regard.
Stuffy nose
Dealing with a stuffy nose can be an uphill battle. Even steam cannot help sometimes. Eucalyptus oil can come in handy in such cases, as it acts as a decongestant. Add eucalyptus oil as well as other medicinal essential oils to the hot water steam you take. A stuffy nose can be a result of an infection or chronic inflammation. Eucalyptus oil helps with both conditions.
Cold sores
Eucalyptus has anti-inflammatory properties, which makes it an effective remedy to alleviate the symptoms of herpes. Using eucalyptus oil on a cold sore can relieve pain and accelerate the healing process. In fact, many over-the-counter ointments and balms for cold sores contain eucalyptus oil as an active ingredient.
Commercial ways to use eucalyptus oil
Eucalyptus oil is a commercially significant product, as it is used in pharmaceuticals, flavoring, and perfume industries. It is also used in candies and chocolates, as well as soaps and detergents. Its other uses are as follows:
1. Penetration enhancer:
Eucalyptus oil acts as a penetration enhancer, i.e. it penetrates the skin and increases the permeability of our skin’s barrier. This property helps the components of eucalyptus oil to reach the deeper layers of skin and produce enhanced results. For example, a skincare product that contains penetration enhancers would be more effective and show quick results than another product that does not contain penetration enhancers. We at BLACKPAINT use eucalyptus oil in many of our products to improve the penetration capacity of our skincare products and also to avail other immense benefits of eucalyptus oil.
2. Aromatherapy
Eucalyptus oil is used in aromatherapy to help relieve mental exhaustion. The oil increases blood circulation, which means more blood reaches the brain. It rejuvenates the mind and pulls it out from sluggishness.
Using eucalyptus oil in aromatherapy also helps to ease the sinus congestion by clearing out the nasal passages. It also removes harmful airborne bacteria that aggravate nasal blockage.
3. Cleaning
Eucalyptus oil is a natural cleaning agent, as it removes grime and grease effectively. It is suitable for use in the kitchen and can be mixed in with other detergents and soaps to amplify the results. It can also be used to wash floors, toilet bowls, windows, countertops, and so on. Its scent makes it a perfect fabric freshener. It also acts as an air cleanser and eliminates mold, which may be the cause of respiratory issues.
4. Haircare
Eucalyptus oil nourishes hair, moisturizes the itchy scalp, and treats dandruff. It can also eliminate lice and be used to deal with scars, bites, and sores. It also improves hair health by providing nourishment to the scalp as well as hair.
5. Painkiller
Inhaling eucalyptus oil can relieve pain because of its cineole and limonene content. Adding it to a warm bath can relax the stiff muscles. Anecdotal evidence tells that a few drops of this oil with water can help alleviate headaches and muscle aches. One study demonstrated that inhaling eucalyptus oil can help with the pain and blood pressure after total knee-replacement surgery.
6. Insect Repellent
Eucalyptus oil is a natural insect repellent. It shuns away bugs, mosquitos, and insects. Research shows that this essential oil is an effective antifeedant, especially in the case of insects that bite. Antifeedant are organic compounds which are produced by plants and help in the inhibition of attack on the plant by the insects and grazing animals.
One study showed that the application of eucalyptus-containing products could protect from biting insects for up to eight hours. This insect-repellent activity can be extended to eight days if the essential oil is applied to clothes. Another study shows that the application of 30 percent of eucalyptus oil can keep mosquitos away for two hours. However, the oil should possess at least 70 percent of its cineole content.
Another study supported the evidence of oil’s toxicity against the mosquitoes and further told that the burning of eucalyptus leaves could be economical protection against mosquitos. One researcher also suggested the use of lemon eucalyptus oil to be safe from West Nile virus—a serious disease carried by mosquitoes.
7. Weed Control
Eucalyptus oil can reduce the germination of harmful weed significantly. One study found that vapors of eucalyptus oil reduce the growth, chlorophyll content, and cellular respiration of weeds through fumigation. An increase in exposure to oil speeds up the decline in weed growth.
Researchers recommend eucalyptus oil as an effective natural way for weed management. Using eucalyptus oil for weed removal is also economical and eco-friendly. Moreover, the oil’s toxicity is species-specific. It means that the other plants are safe from its impact, as it affects the small-seeded crops.
Another study observed the variation in concentrations and the resultant toxic effect. At lower concentrations, the toxic effect is not only less but also reversible. Whereas, the higher levels cause an irreversible effect, particularly at 100ml. At this concentration, the plants show visible wilting and manifest full mortality over time.
8. Acaricide
Several essential oils are effective in dispelling ticks and mites, be it parasitic or others. Eucalyptus oil is one of these oils. It acts as a natural acaricide—a product that kills mites and ticks. Researchers state that multiple species of eucalyptus oils are ecologically safer acaricide. Commercially available products containing the said essential oils give more effective results. One study shows that these products considerably reduce the number of tick bites in humans. Some researchers suggest that eucalyptus oil can be a good choice to reduce tick-borne infections.
Precautions with this oil
Eucalyptus oil is not safe for direct use and must never be used in high concentrations. According to some experts, the oil content should not exceed 25 percent in cosmetic products. It is classified as ‘Schedule 6’ poison, which means it has a moderate potential to be harmful.
Children and pregnant women are more vulnerable to its toxicity. It should not be ingested, as it can lead to seizures or central nervous system depression. If inhaled by a child, a reduced level of consciousness may be experienced. The ingestion of oil has been known to cause death as well.
Breastfeeding women should also avoid exposure to this oil.
Some people also experience dermatitis on exposure to the said oil. For application on the skin, a carrier oil like jojoba oil should be used. Also, always perform a patch test before full application.
Eucalyptus oil can also interact with some medications like those for high cholesterol, psychiatric disorders, acid reflux, and diabetes. If you are taking any medicines, please consult with your healthcare provider before using eucalyptus oil.
References:
http://www.eucalyptusoil.com/eucalyptus-history
https://www.sciencedirect.com/topics/medicine-and-dentistry/eucalyptus-oil
https://biolres.biomedcentral.com/articles/10.1186/0717-6287-48-7
https://www.newdirectionsaromatics.com/blog/products/all-about-eucalyptus-oil.html
https://www.researchgate.net/publication/222750005_Eucalyptus_essential_oil_as_natural_pesticide
https://www.researchgate.net/publication/307869709_Beneficial_and_Healthy_Properties_of_Eucalyptus_Plants_A_Great_Potential_Use
https://www.hindawi.com/journals/ecam/2013/502727/
http://www.altmedrev.com/archive/publications/15/1/33.pdf
https://www.webmd.com/vitamins/ai/ingredientmono-700/eucalyptus
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2374764/
https://www.healthline.com/nutrition/eucalyptus-leaves#section3