by Emirhan Turan, 19 July, 2020
Eucalyptus is an Australian native genus of tall, evergreen, and magnificent tree or shrub cultivated the world wide for its oil, gum, pulp, timber, medicine, and aesthetic values. Eucalyptus belongs to the Myrtaceae family and is represented by around 700 species mostly native to the Australian continent. Eucalyptus trees can grow up to 60 m long which makes them appropriate for timber production. Eucalyptus shrubs can grow in an extreme environment less than 1 m and can be found mainly in Tasmania, Southern, and Western Australia.
‘’Wildfire is a feature of the Australian landscape and many eucalypt species are adapted to fire, and resprout after a fire or have seeds which survive a fire.’’
Eucalyptus have been grown in many other countries as they are fast-growing and have valuable importance as timber, its use as pulpwood, for honey production and/or essential oils extraction. Among the wood and non-wood products essential oil content of Eucalyptus has been identified as the most important one, as it is extensively used in food, pharmaceutical, and perfumery industries.
'’Eucalypts provide food for a large number of animals including koalas, cockatoos, and many insects.’’
Chemical composition of Eucalyptus
Eucalyptus leaves are the source of essential oil that contains 1,8-cineol (49.07 to 83.59%) and α-pinene (1.27 to 26.35%) together with other important chemical components such as b-pinene, a-phellandrene, limonene, terpinen-4-ol, aromadendrene, epiglobulol, piperitone and globulol. The ratio of the constituents in Eucalyptus is changing for each variety. Leaves also contain flavonoids and tannins; flavonoids are plant-based antioxidants, and tannins may help to reduce inflammation.
Eucalyptus oil
Eucalyptus oil is a distilled oil that is coming from the dry leaves of Eucalyptus. The oil is colorless, strong woody and sweet smell. Eucalyptus oils are derived from different varieties of Eucalyptus that have different ingredients and ratios of bioactive compounds. Here are some examples of Eucalyptus oils and origins:
- Eucalyptus polybractea: a small mallee type tree. The single-distilled oil is high in cineole (a colorless, liquid terpene ether with a camphor-like odor and is found in essential oils) and usually assays between 80 and 88 percent.
- Eucalyptus globulus: This variety is the most known Eucalyptus. Its cineole is between 60 and 70 percentage.
- Eucalyptus radiata: The crude oil has a cineole content of 65 to 70 percent with a very refreshing aroma.
Health Benefits
Eucalyptus is used in many health products as an ingredient to reduce symptoms of coughs, colds, and congestion. It also is used in creams and ointments aiming to relieve muscle and joint pain.
- Antimicrobial properties: Studies found that eucalyptus oil may have antibacterial effects on pathogenic bacteria in the upper respiratory tract, including Haemophilus influenza.
- Colds and respiratory problems: Eucalyptus is helping to relieve symptoms of the common cold, cough lozenges, and inhalants. Fresh leaves are used in a gargle to relieve a sore throat, sinusitis, and bronchitis. Several cough medications include eucalyptus oil, for example, Vicks VapoRub.
- Dental care: The antibacterial and antimicrobial properties of eucalyptus have been used in some mouthwash and dental preparations. Eucalyptus appears to be active in fighting bacteria that cause tooth decay and periodontitis.
- Fungal infections and wounds: Studies found the eucalyptus is used to treat skin wounds. Aboriginal medicines used eucalyptus to treat fungal infections and skin wounds.
- Pain relief: Eucalyptus extract may act as a pain reliever due to the essential oil, and research shows that the oil may have analgesic properties.
- Stimulating the immune system: Eucalyptus oil may stimulate an immune system response.
- Other benefits of Eucalyptus may include creating immune against arthritis, flu, blocked nose, burns and wounds, bladder diseases, diabetes.
- Eucalyptus oil is used as insect repellent and pesticide as well. Oil of lemon eucalyptus is recommended as an insect repellant; it is effective at keeping mosquitoes away. E. globulus oil was active against the larvae and pupae of the housefly.
Beyond the benefits of Eucalyptus, they can be hazardous for people as well. Eucalyptus forests are littered with dead branches, as they shed whole and very large branches to conserve water during periods of drought. Camping or working under those wonderful trees can be a threat.
References
Batish, D. R., Singh, H. P., Kohli, R. K., & Kaur, S. (2008). Eucalyptus essential oil as a natural pesticide. Forest ecology and management, 256(12), 2166-2174.
Coppen, J. J. (Ed.). (2002). Eucalyptus: the genus Eucalyptus. CRC Press.
Cermelli, C., Fabio, A., Fabio, G., & Quaglio, P. (2008). Effect of eucalyptus essential oil on respiratory bacteria and viruses. Current microbiology, 56(1), 89-92.
Nagata, H., Inagaki, Y., Tanaka, M., Ojima, M., Kataoka, K., Kuboniwa, M., … & Shizukuishi, S. (2008). Effect of eucalyptus extract chewing gum on periodontal health: a double‐masked, randomized trial. Journal of periodontology, 79(8), 1378-1385.
Salehi, B., Sharifi-Rad, J., Quispe, C., Llaique, H., Villalobos, M., Smeriglio, A., … & Castillo, C. M. S. (2019). Insights into Eucalyptus genus chemical constituents, biological activities and health-promoting effects. Trends in Food Science & Technology, 91, 609-624.
Silva, J., Abebe, W., Sousa, S. M., Duarte, V. G., Machado, M. I. L., & Matos, F. J. A. (2003). Analgesic and anti-inflammatory effects of essential oils of Eucalyptus. Journal of ethnopharmacology, 89(2-3), 277-283.
Takahashi, T., Kokubo, R., & Sakaino, M. (2004). Antimicrobial activities of eucalyptus leaf extracts and flavonoids from Eucalyptus maculata. Letters in applied microbiology, 39(1), 60-64.
https://www.newworldencyclopedia.org/entry/Eucalyptus#Animal_Relationships Access date: 06 July 2020