Health solutions found in nature, everything about eucalyptus

 Hello, today I'm going to blog about eucalyptus oil extracted from eucalyptus leaves, which koalas eat as their staple food. In fact, I thought I knew a lot about it because I mainly write blog posts about the ingredients in our products, but I vaguely thought that eucalyptus is a similar ingredient to menthol. I looked up a lot of papers and did some research for the blog, and I think I learned a lot of new things than I thought.

 

History of Eucalyptus Leaves

Eucalyptus leaves were originally native to Australia and nearby areas. There are about 800 different types, and more than 90% of them are native to Australia. It is said that some of them grew in small quantities in New Guinea, Tasmania, and Indonesia. Even now, eucalyptus leaves cover more than 70% of the forest area in Australia, so they can be considered the core of Australian forests.

For the Australian aborigines of the past, eucalyptus leaves were more than just plants; they were considered medicinal herbs, living tools, symbols of healing and purification, and mythologically spiritual beings. They were used to treat wounds and colds, and eucalyptus trees were used to make bowls, musical instruments (Didjeridu), and boats, and bark painting was famous. In addition, it appears as a major symbol in the Dreamtime, the mythology of the Australian aborigines, and it is believed that the scent and smoke of eucalyptus leaves are the breath of ancestors, so it was believed that by burning eucalyptus leaves in ancestral rites or special ceremonies or walking around with a bunch of eucalyptus leaves in hand, spiritual protection and space purification were achieved. 

Eucalyptol efficacy, effects study

In the 1870s, German chemists distilled/isolated the main active ingredient from eucalyptus oil and named it eucalyptol or 1,8-cineole. In the early 20th century, eucalyptol was actively used in cough/cold medicine, gargles, ointments, etc., and in modern times, eucalyptol has been scientifically proven to have anti-inflammatory, antibacterial, expectorant, and antiviral effects, and is being used in various fields.

Since its discovery, eucalyptus leaves have been brought to attention as a key ingredient in medicinal essential oils due to their refreshing scent and special efficacy and have been planted in various countries around the world. Eucalyptus leaves grow well in any environment and are advantageous for propagation, so they are currently planted in such large numbers that they occupy the second largest plantation area worldwide, between pine (1st) and acacia (3rd). Not only is it highly reproductive, but it is also used in various industrial fields such as pulp, fuel, medicine, and bioenergy, and it is said to be planted to prevent desertification and afforestation due to its rapid growth and root spread. It is said to have a unique characteristic of releasing seeds by heat as a breeding strategy after a forest fire. It is a ‘pyretopic (fire-adapted)’ plant that reproduces actively after a forest fire.

Eucalyptol, which is used in so many ways, has a fatal drawback. It is toxicity. Since it has an antibacterial effect, it can attack normal cells, so it is natural in a way. Eucalyptol has been used in various ways since ancient times, and it has had fatal effects on infants and young children due to excessive inhalation and ingestion. Excessive intake can cause central nervous system depression, vomiting, and coma, and the terpenes, tannins, and aldehydes contained in eucalyptus leaves can cause skin irritation and digestive problems. Because of this, you may be concerned that even products containing small amounts of eucalyptus are dangerous for children. This risk is the risk of drinking more than 1-2ml of eucalyptus oil concentrate. Normally, products containing only a small amount of eucalyptus oil for the nose or mouth do not cause toxicity but rather have antibacterial and antiviral functions in the body, so you do not need to worry.

Surprisingly, there is an animal called a koala that grows only on toxic eucalyptus leaves. It is said that koalas have special digestive organs and detoxification abilities that are adapted to the toxicity of eucalyptus leaves. In addition, they distinguish between 800 types of eucalyptus leaves and only eat about 50 types of eucalyptus leaves that are suitable for them.

However, eucalyptus leaves are low in calories, high in fiber, and difficult to digest, making them a very inefficient source of energy. People probably think that koalas use a lot of energy to digest them, and sleep for 18-22 hours a day to reduce energy consumption. There is no scientific basis for the suspicion that eucalyptus leaves have a sleep-inducing effect.

Eucalyptol and menthol

Eucalyptus is used together with menthol, and they have similar but different functions. The refreshing feeling is similar, but the chemical formulas are different, and the points of action are slightly different.

Category	Eucalyptol	Menthol
Chemical Structure	Monoterpene oxide (1,8-cineole)	Menthane-based alcohol
Main Sources	Eucalyptus, rosemary, basil, etc.	Peppermint, spearmint, etc.
Scent Characteristics	Slightly spicy and refreshing herbal aroma	Strong, cool minty scent
Sensory Effect	Mild cooling sensation, refreshing	Strong cooling sensation, invigorating
Main Benefits	Anti-inflammatory, antimicrobial, expectorant, respiratory relief	Pain relief, itch relief, nasal decongestion
Typical Uses	Cough medicine, mouthwash, air freshener, inhalant	Ointments, patches, nasal sprays, shampoos
Mechanism of Action	Soothes mucous membranes, antimicrobial effects	Stimulates TRPM8 receptors → induces cooling sensation
Safety / Precautions	May cause irritation at high concentrations	May cause skin irritation or convulsions at high concentrations

Simply put, if we look at the effects on humans, eucalyptus has antibacterial and anti-inflammatory effects, and menthol has cooling and analgesic effects. We use eucalyptus and menthol together in our products. As a non-researcher, I thought it was just a fragrance for cooling and refreshing, but I was surprised to find out that it has these functions. 

Finally, Eucalyptus leaves are not just trees; they are a gift from nature that contributes to human health, industry, and environmental recovery. The science, tradition, and potential contained within them will continue to be a part of our lives in more diverse ways in the future. I hope that we can preserve the value of eucalyptus leaves together through sustainable use and deep understanding.

 

References

1. Anti-inflammatory and Asthma Relief Effects
   Title: Anti-inflammatory activity of 1,8-cineole (eucalyptol) in bronchial asthma
   https://pubmed.ncbi.nlm.nih.gov/12645832/
   Author: Juergens et al. (Department Head at Asklepios North Sea Clinic Westerland, Germany)
   Journal: Respiratory Medicine (2003)
   Key Point: The study found that eucalyptol suppresses inflammation in patients with bronchitis and asthma and may serve as an adjunct to steroid medications.
2. Antibacterial and Antiviral Effects
   Title: Antimicrobial activity of Eucalyptus camaldulensis Dehn. plant extracts and essential oils: A review
   https://www.sciencedirect.com/science/article/pii/S0926669019301529?via%3Dihub#sec0075
   Author: Petar Knezevic (Serbia)
   Journal: Industrial Crops and Products (2019)
   Key Point: The essential oils and bark extracts containing eucalyptol show value as antibacterial, antiviral, and antifungal agents.
3. Research on Chronic Obstructive Pulmonary Disease (COPD)
   Title: Concomitant therapy with Cineole (Eucalyptole) reduces exacerbations in COPD: A placebo-controlled double-blind trial
   https://respiratory-research.biomedcentral.com/articles/10.1186/1465-9921-10-69
   Author: Heinrich Worth
   Journal: Respiratory Research, Volume 10, Article 69 (2009)
   Key Point: The study demonstrated that eucalyptol intake had positive effects in COPD patients, including reduction in coughing, mucus production, and improvement in lung function.
4. Antioxidant and Neuroprotective Effects
   Title: 1,8-Cineole ameliorates oxygen-glucose deprivation/reoxygenation-induced ischaemic injury by reducing oxidative stress in rat cortical neuron/glia
   https://pubmed.ncbi.nlm.nih.gov/25088014/
   Author: Sangwoo Ryu
   Journal: Journal of Pharmacy and Pharmacology (2014)
   Key Point: Experimental results indicate that eucalyptol helps suppress oxidative stress and protects nerve cells.
5. Oral Health and Anti-plaque Effects
   Title: Effect of essential oils on oral halitosis treatment: a review
   https://onlinelibrary.wiley.com/doi/10.1111/eos.12745
   Journal: European Journal of Oral Sciences (2020)
   Key Point: Mouthwashes containing eucalyptol have been shown to effectively reduce gingivitis and dental plaque; it is a key ingredient in oral rinses such as Listerine.