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Cannabis flower essential oil, also known as hemp essential oil, is an essential oil obtained by steam distillation from the flowers, panicles (flower cluster), stem, and upper leaves of the hemp plant (Cannabis sativa L.). [1] Hemp essential oil is distinct from hemp seed oil (hemp oil) and hash oil: the former is a vegetable oil that is cold-pressed from the seeds of low-THC varieties of hemp, the latter is a THC-rich extract of dried female hemp flowers (marijuana) or resin (hashish). [2]
A pale yellow liquid, cannabis flower essential oil is a volatile oil that is a mixture of monoterpenes, sesquiterpenes, and other terpenoid compounds. The typical scent of hemp results from about 140 different terpenoids. Beyond terpenes, there exist a number of other minor compounds that can drastically influence the aroma, such as volatile sulfur compounds, [3] esters, and the heterocyclic compounds indole and skatole. [4] The essential oil is manufactured from both low-THC ("fibre-type") and high-THC ("drug-type") varieties of hemp. As most of the phytocannabinoids are nearly insoluble in water, hemp essential oil contains only traces of cannabinoids. Even in "drug-type" hemp, the THC content of the essential oil does not exceed 0.08%. Most of the material is produced in Canada, as well as small scale cultivations in Switzerland and Germany. [5]
Hemp essential oil is used as a scent in perfumes, cosmetics, soaps, and candles. It is also used as a flavoring in foods, [6] primarily candy and beverages.
The yield depends on the hemp type (drug, fiber) and pollination; sex, age, and part of the plant; cultivation (indoor, outdoor etc.); harvest time and conditions; drying; and storage. For example, fresh buds from an Afghani variety yielded 0.29% essential oil. Drying and storage reduced the content from 0.29% to 0.20% after 1 week, and to 0.13% after 3 months. Monoterpenes showed a significantly greater loss than sesquiterpenes, but none of the major components completely disappeared in the drying process. [7]
About 1.3 L of essential oil per ton resulted from freshly harvested outdoor-grown hemp, corresponding to about 10 L/ha. The yield of nonpollinated ("sinsemilla") hemp at 18 L/ha was more than twofold compared with pollinated hemp (8 L/ha). [7]
Sixty-eight components were detected by GC and GC/mass spectrometry (MS) in fresh bud oil distilled from high-potency, indoor-grown hemp. The 57 identified constituents were 92% monoterpenes, 7% sesquiterpenes, and approx. 1% other compounds (ketones, esters). The dominating monoterpenes were myrcene (67%) and limonene (16%). [7]
In the essential oil from outdoor-grown hemp, the monoterpene concentration varied between 47.9 and 92.1% of the total terpenoid content. The sesquiterpenes ranged from 5.2 to 48.6%. The most abundant monoterpene was β-myrcene, followed by trans-caryophyllene, α-pinene, trans-ocimene, and α-terpinolene. [7]
Another report said there were 140 terpenoids, dominated by α-pinene and limonene which together often comprise 75% of the live plant's volatiles. However, extracted essential oils can change in composition, and the live plant, dried plant and essential oil can smell rather different. [8]
Even in "drug-type" hemp, the THC content of the essential oil was not more than 0.08%. [7]
In the essential oil of five different European hemp cultivars, the dominating terpenes were myrcene (21.1–35.0 %), α-pinene (7.2–14.6 %), α-terpinolene (7.0–16.6 %), trans-caryophyllene (12.2.–18.9 %), and α-humulene (6.1–8.7 %). The main differences between the cultivars were found in the contents of α-terpinolene and α-pinene. [7]
Other terpenoids present only in traces are sabinene, α-terpinene, 1,8-cineole (eucalyptol), pulegone, γ-terpinene, terpineol-4-ol, bornyl acetate, α-copaene, alloaromadendrene, viridiflorene, β-bisabolene, γ-cadinene, trans-β-farnesene, trans-nerolidol, and β-bisabolol. [7]
The major alkane present in an essential oil obtained by extraction and steam distillation was the n-C29 alkane nonacosane (55.8 and 10.7%, respectively). [7]
Compound | % of total |
---|---|
![]() Myrcene | 29.4–65.8 |
![]() α-Pinene | 2.3–31.0 |
![]() β-Pinene | 0.9–7.8 |
![]() delta-3-Carene | trace–3.5 |
![]() Limonene | 0.2–6.9 |
![]() β-phellandrene | 0.2–0.6 |
![]() cis-Ocimene | trace–0.3 |
![]() trans-Ocimene | 0.3–10.2 |
![]() α-Terpinolene | trace–23.8 |
![]() α-Bergamotene | trace–0.8 |
![]() trans-Caryophyllene | 3.8–37.5 |
![]() α-Humulene | 0.7–7.4 |
![]() β-Farnesene | trace–1.4 |
β-Selinene | trace–0.5 |
Selina-3,7(11)-diene | trace–0.7 |
Caryophyllene oxide | trace–11.3 |
Total monoterpenes | 47.9–92.1 |
Total sesquiterpenes | 4.0–47.5 |
The various terpenes in cannabis have antifungal, antimicrobial, antiviral and insect repellent functions that could be commercially valuable when used externally. [8]
Cannabis essential oils that are cannabinoid-free have been tested for central nervous effects. Natural monoterpenes and sesquiterpenes from cannabis flowers have relaxing, sedative and anti-depressant effects when inhaled. Their application in aromatherapy is increasing, but the high price of the natural oil (50$ per milliliter) is a limiting factor. [9]
In Switzerland and Austria, specific landraces with high essential oil content but no discernible amounts of cannabinoids have been developed for the purpose of flavoring beverage products. For those applications, oils with high monoterpene percentages (but a low alpha-humulene or caryophyllene oxide concentration) are desirable. [10] [11]
Terpenes used in THC vaping products, legal in some jurisdictions in the United States, are not true cannabis terpenes, but synthetic and racemic with potential health hazards. Due to health promoting effects, natural THC-free cannabis flower oil is the preferred ingredient in the legal European market. Unregulated additives in US vaping products have led to serious health consequences, including fatal outcomes. [12]
Terpenes are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. In plants, terpenes and terpenoids are important mediators of ecological interactions, while some insects use some terpenes as a form of defense. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control.
Cannabis sativa is an annual herbaceous flowering plant. The species was first classified by Carl Linnaeus in 1753. The specific epithet sativa means 'cultivated'. Indigenous to Eastern Asia, the plant is now of cosmopolitan distribution due to widespread cultivation. It has been cultivated throughout recorded history and used as a source of industrial fiber, seed oil, food, and medicine. It is also used as a recreational drug and for religious and spiritual purposes.
Pinene is a collection of unsaturated bicyclic monoterpenes. Two geometric isomers of pinene are found in nature, α-pinene and β-pinene. Both are chiral. As the name suggests, pinenes are found in pines. Specifically, pinene is the major component of the liquid extracts of conifers. Pinenes are also found in many non-coniferous plants such as camphorweed (Heterotheca) and big sagebrush.
Myrcene, or β-myrcene, is a monoterpene. A colorless oil, it occurs widely in essential oils. It is produced mainly semi-synthetically from Myrcia, from which it gets its name. It is an intermediate in the production of several fragrances. α-Myrcene is the name for the isomer 2-methyl-6-methylene-1,7-octadiene, which has not been found in nature.
Caryophyllene, more formally (−)-β-caryophyllene (BCP), 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, copaiba, 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.
Ocimenes are a group of isomeric hydrocarbons. The ocimenes are monoterpenes found within a variety of plants and fruits. α-Ocimene and the two β-ocimenes differ in the position of the isolated double bond: it is terminal in the alpha isomer. α-Ocimene is cis-3,7-dimethyl-1,3,7-octatriene. β-Ocimene is trans-3,7-dimethyl-1,3,6-octatriene. β-Ocimene exists in two stereoisomeric forms, cis and trans, with respect to the central double bond. The ocimenes are often found naturally as mixtures of the various forms. The mixture, as well as the pure compounds, are oils with a pleasant odor. They are used in perfumery for their sweet herbal scent, and are believed to act as plant defense and have anti-fungal properties. Like the related acyclic terpene myrcene, ocimenes are unstable in air. Like other terpenes, the ocimenes are nearly insoluble in water, but soluble in common organic solvents.
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. It is one of the two isomers of pinene, the other being β-pinene. An alkene, it contains a reactive four-membered ring. It is found in the oils of many species of many coniferous trees, notably the Pinus and Picea species. 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 enantiomers' racemic mixture is present in some oils such as eucalyptus oil and orange peel oil.
β-Pinene is a monoterpene, an organic compound found in plants. It is one of the two isomers of pinene, the other being α-pinene. It is a colorless liquid soluble in alcohol, but not water. It has a woody-green pine-like smell.
Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modifications such as oxidation or rearrangement produce the related sesquiterpenoids. A recent study conducted in the Cosmics Leaving Outdoor Droplets large cloud chamber at CERN, has identified sesquiterpenes—gaseous hydrocarbons that are released by plants—as potentially playing a major role in cloud formation in relatively pristine regions of the atmosphere.
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries.
Terpineol is any of four isomeric monoterpenoids. Terpenoids are terpene that are modified by the addition of a functional group, in this case, an alcohol. Terpineols have been isolated from a variety of sources such as cardamom, cajuput oil, pine oil, and petitgrain oil. Four isomers exist: α-, β-, γ-terpineol, and terpinen-4-ol. β- and γ-terpineol differ only by the location of the double bond. Terpineol is usually a mixture of these isomers with α-terpineol as the major constituent.
Cryptocarya agathophylla is a member of the laurel family, Lauraceae, and originates in Madagascar.
Hash oil or cannabis oil is an oleoresin obtained by the extraction of cannabis or hashish. It is a cannabis concentrate containing many of its resins and terpenes – in particular, tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids. Hash oil is usually consumed by smoking, vaporizing or eating. Preparations of hash oil may be solid or semi-liquid colloids depending on both production method and temperature and are usually identified by their appearance or characteristics. Color most commonly ranges from transparent golden or light brown, to tan or black. There are various extraction methods, most involving a solvent, such as butane or ethanol.
The entourage effect is a marketing slogan that purports cannabis compounds other than tetrahydrocannabinol (THC) act synergistically with it to modulate the overall psychoactive effects of the plant.
The following outline is provided as an overview of and topical guide to the plant Cannabis sativa and its relatives Cannabis indica and Cannabis ruderalis, the drug cannabis (drug) and the industrial product hemp.
Super Lemon Haze is a sativa-dominant cannabis strain in the haze family of strains. It was originally bred by Franco Loja from the Netherlands-based Green House Seed Co. as a cross between two other strains: Lemon Skunk and Super Silver Haze.
Manuka oil is an essential oil obtained from the steam distillation of the leaves and small branches of the tree Leptospermum scoparium . Though it is used in a wide range of cosmetics, cosmeceuticals and naturopathic and topical medications, manuka oil is a relatively new development; it was first identified during the 1970s and has been produced commercially since the 1980s and investigated by global research teams since then.
Cannabis (/ˈkænəbɪs/) is commonly known as marijuana or hemp and has two known strains: Cannabis sativa and Cannabis indica, both of which produce chemicals to deter herbivory. The chemical composition includes specialized terpenes and cannabinoids, mainly tetrahydrocannabinol (THC), and cannabidiol (CBD). These substances play a role in defending the plant from pathogens including insects, fungi, viruses and bacteria. THC and CBD are stored mostly in the trichomes of the plant, and can cause psychological and physical impairment in the user, via the endocannabinoid system and unique receptors. THC increases dopamine levels in the brain, which attributes to the euphoric and relaxed feelings cannabis provides. As THC is a secondary metabolite, it poses no known effects towards plant development, growth, and reproduction. However, some studies show secondary metabolites such as cannabinoids, flavonoids, and terpenes are used as defense mechanisms against biotic and abiotic environmental stressors.
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