Eucalyptus is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with other genera in the tribe Eucalypteae, they are commonly known as eucalypts. Plants in the genus Eucalyptus have bark that is either smooth, fibrous, hard or stringy, leaves with oil glands, and sepals and petals that are fused to form a "cap" or operculum over the stamens. The fruit is a woody capsule commonly referred to as a "gumnut".
Myrtaceae or the myrtle family is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pohutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All species are woody, contain essential oils, and have flower parts in multiples of four or five. The leaves are evergreen, alternate to mostly opposite, simple, and usually entire. The flowers have a base number of five petals, though in several genera the petals are minute or absent. The stamens are usually very conspicuous, brightly coloured and numerous.
An essential oil is a concentrated hydrophobic liquid containing volatile chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetherolea, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is "essential" in the sense that it contains the "essence of" the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term "essential" used here does not mean indispensable or usable by the human body, as with the terms essential amino acid or essential fatty acid, which are so called because they are nutritionally required by a given living organism.
Anethole is an organic compound that is widely used as a flavoring substance. It is a derivative of phenylpropene, a type of aromatic compound that occurs widely in nature, in essential oils. It contributes a large component of the odor and flavor of anise and fennel, anise myrtle (Myrtaceae), liquorice (Fabaceae), camphor, magnolia blossoms, and star anise (Illiciaceae). Closely related to anethole is its isomer estragole, abundant in tarragon (Asteraceae) and basil (Lamiaceae), that has a flavor reminiscent of anise. It is a colorless, fragrant, mildly volatile liquid. Anethole is only slightly soluble in water but exhibits high solubility in ethanol. This trait causes certain anise-flavored liqueurs to become opaque when diluted with water, the ouzo effect.
Eucalyptus globulus, commonly known as southern blue gum, is a species of tall, evergreen tree endemic to southeastern Australia. It 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. There are four subspecies, each with a different distribution, occurring in New South Wales, Victoria and Tasmania.
Eucalyptol is a natural organic compound that is a colorless liquid. It is a cyclic ether and a monoterpenoid.
Caryophyllene, more formally (−)-β-caryophyllene, is a natural bicyclic sesquiterpene that is a constituent of many essential oils, especially clove oil, the oil from the stems and flowers of Syzygium aromaticum (cloves), the essential oil of Cannabis sativa, rosemary, and hops. It is usually found as a mixture with isocaryophyllene and α-humulene, a ring-opened isomer. Caryophyllene is notable for having a cyclobutane ring, as well as a trans-double bond in a 9-membered ring, both rarities in nature.
Humulene, also known as α-humulene or α-caryophyllene, is a naturally occurring monocyclic sesquiterpene (C15H24), containing an 11-membered ring and consisting of 3 isoprene units containing three nonconjugated C=C double bonds, two of them being triply substituted and one being doubly substituted. It was first found in the essential oils of Humulus lupulus (hops), from which it derives its name. Humulene is an isomer of β-caryophyllene, and the two are often found together as a mixture in many aromatic plants.
Phellandrenes are a pair of organic compounds that have a similar molecular structure and similar chemical properties. α-Phellandrene and β-phellandrene are cyclic monoterpenes and are double-bond isomers. In α-phellandrene, both double bonds are endocyclic and in β-phellandrene, one of them is exocyclic. Both are insoluble in water, but miscible with ether.
The terpinenes are a group of isomeric hydrocarbons that are classified as monoterpenes. They each have the same molecular formula and carbon framework, but they differ in the position of carbon-carbon double bonds. α-Terpinene has been isolated from cardamom and marjoram oils, and from other natural sources. β-Terpinene has no known natural source but has been prepared from sabinene. γ-Terpinene and δ-terpinene have been isolated from a variety of plant sources. They are all colorless liquids with a turpentine-like odor.
α-Pinene is an organic compound of the terpene class, one of two isomers of pinene. It is an alkene and it contains a reactive four-membered ring. It is found in the oils of many species of many coniferous trees, notably the pine. It is also found in the essential oil of rosemary and Satureja myrtifolia. Both enantiomers are known in nature; (1S,5S)- or (−)-α-pinene is more common in European pines, whereas the (1R,5R)- or (+)-α-isomer is more common in North America. The racemic mixture is present in some oils such as eucalyptus oil and orange peel oil.
Eucalyptus oil is the generic name for distilled oil from the leaf of Eucalyptus, a genus of the plant family Myrtaceae native to Australia and cultivated worldwide. Eucalyptus oil has a history of wide application, as a pharmaceutical, antiseptic, repellent, flavouring, fragrance and industrial uses. The leaves of selected Eucalyptus species are steam distilled to extract eucalyptus oil.
Corymbia citriodora, commonly known as lemon-scented gum or spotted gum, is a species of tall tree that is endemic to north-eastern Australia. It has smooth white to pink bark, narrow lance-shaped to curved adult leaves, flower buds in groups of three, white flowers and urn-shaped or barrel-shaped fruit.
Eucalyptus olida is a species of small to medium-sized tree that is endemic to a restricted area of New South Wales. It has rough, flaky and fibrous bark on the trunk and larger branches, lance-shaped to curved adult leaves, flower buds in groups of seven to fifteen or more, white flowers and barrel-shaped or bell-shaped fruit.
Eucalyptus dives, commonly known as the broad-leaved peppermint or blue peppermint, is a species of tree that is endemic to south-eastern Australia. It has rough, finely fibrous bark on the trunk and larger branches, smooth bark above, lance-shaped or curved adult leaves, flower buds in groups of eleven or more, white flowers and cup-shaped, hemispherical or conical fruit.
Eucalyptus radiata, commonly known as the narrow-leaved peppermint or Forth River peppermint, is a species of tree that is endemic to south-eastern Australia. It has rough, fibrous to flaky bark on the trunk and larger branches, smooth grey bark on the thinner branches, lance-shaped to curved or almost linear leaves, flower buds in groups of eleven to twenty or more, white flowers and cup-shaped, hemispherical or shortenend spherical fruit.
Eucalyptus piperita, commonly known as Sydney peppermint and urn-fruited peppermint, is a small to medium forest tree native to New South Wales, Australia.
Eucalyptus tereticornis, commonly known as forest red gum, blue gum or red irongum, is a species of tree that is native to eastern Australia and southern New Guinea. It has smooth bark, lance-shaped to curved adult leaves, flower buds in groups of seven, nine or eleven, white flowers and hemispherical fruit.
Eucalyptus oleosa, commonly known as the red mallee, glossy-leaved red mallee, acorn mallee, oil mallee or giant mallee, is a tree or mallee that is native to Australia. The leaves were once harvested for the production of cineole based eucalyptus oil. Eucalyptus cneorifolia is now the predominant strain used in production due to a higher oil content in new growth.
Aromatherapy is a pseudoscience based on the usage of aromatic materials, including essential oils, and other aroma compounds, with claims for improving psychological or physical well-being. It is offered as a complementary therapy or as a form of alternative medicine, the first meaning alongside standard treatments, the second instead of conventional, evidence-based treatments.
