Eucalyptus (Eucalyptus globulus)
Botany, Geographical Distribution, and Horticultural Information of Eucalyptus (Eucalyptus globulus)
Botanical Description:
Eucalyptus globulus, commonly known as southern blue gum or blue gum, is a species of flowering plant in the Myrtaceae family. It is a tall, evergreen tree endemic to southeastern Australia. This Eucalyptus species has mostly smooth bark, juvenile leaves that are whitish and waxy on the lower surface, glossy green, lance-shaped adult leaves, glaucous, ribbed flower buds arranged singly or in groups of three or seven in leaf axils, white flowers, and woody fruit. The tree typically grows to a height of 45 m but can reach up to 90–100 m under ideal conditions.
Subspecies:
There are four subspecies of Eucalyptus globulus:
1. Eucalyptus globulus subsp. bicostata (Victorian blue gum or eurabbie)
2. Eucalyptus globulus subsp. globulus (Tasmanian blue gum)
3. Eucalyptus globulus subsp. maidenii (Maiden’s gum)
4. Eucalyptus globulus subsp. pseudoglobulus (Victorian eurabbie)
Each subspecies has a characteristic arrangement of its flower buds and a different distribution across Australia, occurring in New South Wales, Victoria, and Tasmania.
Geographical Distribution:
Eucalyptus globulus grows in forests in New South Wales, Victoria, and Tasmania, including some Bass Strait Islands. The subspecies have specific distributions within these regions. The tree has also naturalized in non-native regions such as Spain, Portugal, southern Europe, southern Africa, New Zealand, the western United States (California), Hawaii, and Macaronesia. While considered a cash crop due to its fast growth, it is controversial as a plantation tree; considered problematic in many regions and possibly invasive due to the difficulty of removing it and also the ease with which can blaze up, making it prone to forest fires.
Horticultural Aspects:
Eucalyptus globulus is one of the most extensively planted eucalypts due to its rapid growth and adaptability to various conditions. It is particularly well-suited to countries with a Mediterranean-type climate but also thrives in high altitudes in the tropics. The tree comprises a significant portion of plantation hardwood in Australia, with approximately 4,500 km² planted.
Uses:
–Timber: The timber is yellow-brown, fairly heavy, with an interlocked grain. It is used in construction, fence posts, and poles.
–Pulpwood: Eucalyptus globulus is a major source of pulpwood. *
–Essential Oil: The leaves are steam distilled to extract eucalyptus oil, which has therapeutic, perfumery, flavoring, antimicrobial, and biopesticide properties. Eucalyptus globulus is the primary source of global eucalyptus oil production.
–Herb Tea: The leaves are also used as a herbal tea.
* Pulpwood refers to timber grown or harvested primarily for the production of paper and pulp. The wood from these trees is processed into pulp, a fibrous material that serves as the raw material for producing various paper products, including writing paper, cardboard, and other paper-based items.
In the case of Eucalyptus globulus, its wood is particularly valued for pulp production due to its high-quality fibers, which contribute to the strength and smoothness of the paper produced. Eucalyptus trees grow rapidly and have a high cellulose content with low lignin, making them an efficient and sustainable choice for pulp and paper manufacturing. The wood from these trees is typically processed in mills where it is chipped, chemically treated, and mechanically or chemically pulped to separate the fibers, which are then used in papermaking.
References:
1. Wikipedia: Eucalyptus globulus – https://en.wikipedia.org/wiki/Eucalyptus_globulus
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History, Traditional Herbal & Culinary Uses of Eucalyptus (Eucalyptus globulus)
Historical Background:
Eucalyptus globulus, commonly known as the southern blue gum or blue gum, is a species of flowering plant in the Myrtaceae family. It is native to southeastern Australia and was first formally described in 1800 by the French botanist Jacques Labillardière. The species name ‘globulus’ refers to the shape of the fruit, resembling a small sphere or ball.
Traditional Uses:
The traditional uses of Eucalyptus globulus are primarily centered around its essential oil, extracted from the leaves. Indigenous Australians used eucalyptus leaves for various medicinal purposes. The leaves were often crushed and inhaled to relieve nasal congestion and other respiratory ailments. They also applied the leaves to wounds to prevent infection and promote healing.
Herbal Medicine:
In herbal medicine, Eucalyptus globulus has been used for its antiseptic properties. The oil extracted from the leaves is known for its antimicrobial and biopesticide properties. It has been used to treat wounds, fungal infections, and as a remedy for fevers and colds. The oil’s high cineole content is responsible for its therapeutic effects, including antimicrobial, anti-inflammatory, and antioxidant properties.
Culinary Uses:
While not widely known for its culinary uses, the leaves of Eucalyptus globulus have been used to make herbal teas. These teas were traditionally consumed for their health benefits, particularly for treating colds and reducing fevers.
Modern Applications:
Today, Eucalyptus globulus remains a significant source of eucalyptus oil, which is used in various products, including cough syrups, ointments, and inhalants for relieving symptoms of colds and respiratory infections. The oil is also used in aromatherapy and as a natural insect repellent.
References:
1. Wikipedia: Eucalyptus globulus – https://en.wikipedia.org/wiki/Eucalyptus_globulus
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Pharmacological and Medicinal Studies on Eucalyptus globulus
Chemical Composition and Therapeutic Effects:
Eucalyptus globulus, commonly known as the Tasmanian Blue Gum, is renowned for its diverse medicinal properties. The essential oil derived from E. globulus is rich in 1,8-cineole, macrocarpal C, terpenes, oleanolic acid, and tannins. These components contribute to its wide range of therapeutic effects. Studies have demonstrated that E. globulus exhibits antibacterial, antifungal, antidiabetic, anticancer, anthelmintic, antiviral, antioxidant, anti-inflammatory properties, and can stimulate the immune response. Additionally, it offers protection against UV-B radiation and aids in wound healing. The leaf extract of Eucalyptus is also used as a food additive in the industry. Despite its varied therapeutic effects, more clinical studies are recommended to confirm these pharmacological activities.
Pharmacological Aspects and Diverse Strengths:
Eucalyptus globulus is a rich source of phytochemicals, including flavonoids, alkaloids, tannins, and propanoids, found in its leaves, stems, and roots. These compounds endow the plant with anti-inflammatory, anticancer, antibacterial, antiseptic, and astringent properties. However, it’s important to note that while Eucalyptus has many benefits, it also poses some ecological concerns, such as restricting the germination of other species and potentially detrimental effects on soil micro and macro fauna.
Antimicrobial and Antioxidant Properties:
The phytochemical constituents of Eucalyptus globulus contribute to its significant antimicrobial and antioxidant activities. These properties are increasingly important in the context of rising antibiotic resistance and the limitations of synthetic antioxidants. Eucalyptus extracts and oils could serve as eco-friendly, plant-based alternatives for controlling insects, weeds, and plant pathogens, reducing reliance on synthetic chemicals.
Traditional and Contemporary Uses:
Historically, Eucalyptus globulus has been used for various purposes. Its essential oil contains esters, carboxylic acids, aldehydes, 1.8 cineole, and cryptophone. These components contribute to its anti-inflammatory, analgesic, antinociceptive, antimicrobial, antifungal, antiviral, and antioxidant properties. The plant’s diverse chemical composition underpins its nutritional and therapeutic value.
References:
1. “Therapeutic Effect, Chemical Composition, Ethnobotanical Profile of Eucalyptus globulus: A Review” – https://dx.doi.org/10.2174/1570178617999200807213043
2. “A REVIEW ON EUCALYPTUS GLOBULUS: A DIVINE MEDICINAL HERB” – https://www.researchgate.net/publication/342976633_An_approach_on_phytochemistry_and_pharmacological_studies_of_Eucalyptus_globulus_plant_parts
3. “Phytochemical Properties and Diverse Beneficial Roles of Eucalyptus globulus Labill.: A Review” – https://www.mdpi.com/2311-7524/7/11/450
4. “A Review on Eucalyptus Globulus – An Authentic Herb” – https://dx.doi.org/10.9734/jpri/2021/v33i53b33686
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Here is a list of specific phytochemical molecules identified in Eucalyptus globulus:
1. 1,8-Cineole (Eucalyptol): This is the major component of the essential oil of Eucalyptus leaves, widely used in flavoring, fragrance, and cosmetics due to its pleasant spicy aroma and taste.
2. Aromadendrene: Identified in the essential oil of hydro-distilled fruits, it exhibits antibacterial activity.
3. Globulol: Predominant in the fruit oils extracted from plants growing in certain regions, contributing to the antibacterial activity of the oil.
4. β-Eudesmol: A significant compound identified in the aqueous ethanol extract of Eucalyptus leaves.
5. γ-Eudesmol: Another compound found in the aqueous ethanol extract of the leaves.
6. Alloaromadendrene: Identified in the pyrolysis gas chromatography-mass spectrometry analysis of the leaves’ aqueous ethanol extract.
7. α-Selinene and α-Gurgujene: Present in low concentrations in the leaves’ aqueous ethanol extract.
8. Guaiacol, Syringol, o-Cymene, Catechol, and Phenol: Associated with the presence of small fragments of lignin and lignin-derived monomeric products in the leaf extracts.
9. Betulinic, Betulonic, Oleanolic, Ursolic, 3-Acetyloleanolic, and 3-Acetylursolic Acids: Major triterpenic acids identified in the leaf extracts, considered valuable pharmaceutical compounds.
10. β-Amirine, β-Sitosterol, Palmitic Acid, and Aliphatic Alcohols: Found in the bark of Eucalyptus globulus.
11. Gallotannins: Abundant in the aqueous extract of the bark, contributing to its antioxidant properties.
12. Hederagenin, 23-Hydroxybetulinic Acid, Maslinic Acid, Corosolic Acid, Arjunolic Acid, Asiatic Acid, Caulophyllogenin, and Madecassic Acid: Polyhydroxy triterpenoid acids identified in the milled wood of mature Eucalyptus globulus trees.
13. Borneol, Linalool, Cineol, Geranyl Acetate, Anethol, and Saffrol: Valuable phytoconstituents in the essential oil from extracted leaves, contributing to its anthelmintic activity.
14. Rutin, Tannic Acid, Vanillic Acid, and Ascorbic Acid: Polyphenolic compounds identified in the Fourier Transform Infrared Spectrophotometer analysis of the leaf extracts.
15. β-Pinene, α-Pinene: Major constituents of the essential oil along with 1,8 cineole.
These individual molecules highlight the rich and diverse phytochemical profile of Eucalyptus globulus, underlining its potential in various pharmaceutical and industrial applications.
References:
1. “Phytochemical Properties and Diverse Beneficial Roles of Eucalyptus globulus Labill.: A Review” – https://www.mdpi.com/2311-7524/7/11/450
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Contraindications and Safety of Eucalyptus globulus
Contraindications:
1. Oral Consumption: Eucalyptus globulus should never be taken orally as it is toxic if consumed by mouth. It may interact with several medications and can cause severe symptoms including stomach pain, dizziness, muscle weakness, feelings of suffocation, drowsiness, seizures, and coma.
2. Children Under 30 Months: The use of Eucalyptus globulus in children under 30 months of age is contraindicated due to the risk of severe toxicity.
3. Interaction with Medications: Eucalyptus oil may interact with medications like albuterol for lung conditions and CNS depressants.
Safety:
1. Topical and Inhalation Use: When used topically or for inhalation, Eucalyptus globulus is generally considered safe. However, it should be used in recommended doses to avoid adverse effects.
2. Eucalyptol: Eucalyptol, a chemical removed from eucalyptus oil, is possibly safe when taken by mouth for up to 12 weeks in controlled doses.
3. Handling Precautions: Adequate ventilation is necessary when handling Eucalyptus globulus to avoid skin and eye contact and prevent inhalation of high concentrations.
4. Toxicity: Eucalyptus oil is highly toxic, and small ingestions of pure oil (≥5 mL) can lead to severe symptoms. Symptoms of eucalyptus poisoning can include nausea, vomiting, diarrhea, and rapid onset of neurological symptoms.
5. Neurotoxicity: Eucalyptus oil is rapidly absorbed and primarily exhibits neurotoxicity, which can manifest as seizures and coma.
6. Elimination: The elimination of eucalyptol, a major component of eucalyptus oil, may be largely via the pulmonary route.
7. Cosmetic Use: In cosmetics, Eucalyptus globulus-derived ingredients are considered safe in the present practices of use and concentration when formulated to be non-sensitizing.
References:
1. “Eucalyptus: Uses, Side Effects, Precautions, and More” – https://www.verywellhealth.com/eucalyptus-uses-benefits-side-effects-dosage-7483449
2. “Eucalyptus Information” – https://www.mountsinai.org/health-library/herb/eucalyptus
3. “Eucalyptus: Health Benefits, Side Effects, Uses, Dose & Precautions” – https://www.rxlist.com/supplements/eucalyptus.htm
4. “Community herbal monograph on Eucalyptus globulus Labill., Eucalyptus polybractea R.T. Baker and/or Eucalyptus smithii R.T. Baker” – https://www.ema.europa.eu/en/documents/herbal-monograph/final-community-herbal-monograph-eucalyptus-globulus-labill-eucalyptus-polybractea-rt-baker-andor-eucalyptus-smithii-rt-baker-aetheroleum_en.pdf
5. “Safety Data Sheet Organic Eucalyptus Essential Oil (Eucalyptus globulus)” – https://www.nhrorganicoils.com/uploads/20160706135904e_Eucalyptus_Globulus_SDS.pdf
6. “Clinical Practice Guidelines: Eucalyptus Oil Poisoning” – https://www.rch.org.au/clinicalguide/guideline_index/Eucalyptus_Oil_Poisoning/
7. “Eucalyptus Oil – an overview” – https://www.sciencedirect.com/topics/medicine-and-dentistry/eucalyptus-oil
8. “Eucalyptus contraindications” – https://www.botanical-online.com/en/medicinal-plants/eucalyptus-contraindications
9. “EUCALYPTUS: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews” – https://www.webmd.com/vitamins/ai/ingredientmono-700/eucalyptus