Cannabis flower essential oil, also known as hemp essential oil, is an essential oil obtained by steam distillation from the flowers,

panicles A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are ...

(flower cluster), stem, and upper leaves of the hemp plant (''Cannabis sativa L''.). Hemp essential oil is distinct from hemp seed oil (hemp oil) and

hash oil Hash oil or cannabis oil, is an oleoresin obtained by the extraction (chemistry), extraction of cannabis or hashish. It is a cannabis concentrate containing many of its resins and terpenes – in particular, tetrahydrocannabinol (THC), cannabid ...

: the former is a

vegetable oil Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, ...

that is cold-pressed from the seeds of low- THC varieties of hemp, the latter is a THC-rich

extract An extract is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol, oil or water. Extracts may be sold as tinctures, absolutes or in powder form. The aromatic principles of many spices, nuts ...

of dried female hemp flowers (

marijuana Cannabis, also known as marijuana among other names, is a psychoactive drug from the cannabis plant. Native to Central or South Asia, the cannabis plant has been used as a drug for both recreational and entheogenic purposes and in variou ...

) or resin (

hashish Hashish ( ar, حشيش, ()), also known as hash, "dry herb, hay" is a cannabis (drug), drug made by compressing and processing parts of the cannabis plant, typically focusing on flowering buds (female flowers) containing the most trichomes. Eu ...

). A pale yellow liquid, cannabis flower essential oil is a volatile oil that is a mixture of

monoterpene 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 func ...

sesquiterpene 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 modifica ...

s, and other

terpenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes ...

compounds. The typical scent of hemp results from about 140 different terpenoids. 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 Cannabinoids () are several structural classes of compounds found in the cannabis plant primarily and most animal organisms (although insects lack such receptors) or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tet ...

. 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. Hemp essential oil is used as a scent in perfumes, cosmetics, soaps, and candles. It is also used as a flavoring in foods, primarily candy and beverages.

Yield

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. 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).

Constituents

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 (

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bon ...

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

s). The dominating monoterpenes were myrcene (67%) and

limonene Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels. The -isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring ...

(16%). 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 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 co ...

, trans- ocimene, and α- terpinolene. Another report said there were 140 terpenoids, dominated by α-

and

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. Even in "drug-type" hemp, the THC content of the essential oil was not more than 0.08%. In the essential oil of five different European hemp cultivars, the dominating terpenes were myrcene (21.1–35.0 %), α-

(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-

. Other terpenoids present only in traces are sabinene, α- terpinene, 1,8- cineole (

eucalyptol Eucalyptol is a monoterpenoid. A colorless liquid, it is a bicyclic ether. Eucalyptol has a fresh mint-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up ~70% - 90% of euc ...

), pulegone, γ- terpinene, terpineol-4-ol,

bornyl acetate Bornyl acetate is a chemical compound. Its molecular formula is C12H20O2 and its molecular weight is 196.29 g/mol. It is the acetate ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least o ...

, α- copaene, alloaromadendrene, viridiflorene, β-

bisabolene Bisabolenes are a group of closely related natural chemical compounds which are classified as sesquiterpenes. Bisabolenes are produced from farnesyl pyrophosphate (FPP) and are present in the essential oils of bisabol, and of a wide variety of o ...

, γ- cadinene, trans-β- farnesene, trans- nerolidol, and β- bisabolol. The major

alkane In organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms tha ...

present in an essential oil obtained by extraction and steam distillation was the n-C₂₉ alkane nonacosane (55.8 and 10.7%, respectively).

Uses

The various terpenes in cannabis have antifungal, antimicrobial, antiviral and insect repellent functions that could be commercially valuable when used externally. Cannabis essential oils that are cannabinoid-free have been tested for central nervous effects. Natural monoterpenes and

sesquiterpenes 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 modificati ...

from cannabis flowers have relaxing, sedative and anti-depressant effects when inhaled. Their application in

aromatherapy Aromatherapy is based on the usage of aromatic materials including essential oils and other aroma compounds, with claims for improving psychological and physical well-being. It is offered as a complementary therapy or as a form of alternative ...

is increasing, but the high price of the natural oil (50$ per milliliter) is a limiting factor. 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. Terpenes used in THC vaping products, legal in some jurisdictions in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, are not true cannabis terpenes, but synthetic and

racemic In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

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.

References

Sources

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External links

Hemp Essential Oil: Sweet Smell of Success
{{cannabis Essential oils Preparations of cannabis