Cannabis flower essential oil, also known as hemp essential oil, is an

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the ...

obtained by steam distillation from the flowers, panicles (flower cluster), stem, and upper leaves of the

hemp Hemp, or industrial hemp, is a plant in the botanical class of ''Cannabis sativa'' cultivars grown specifically for industrial and consumable use. It can be used to make a wide range of products. Along with bamboo, hemp is among the fastest ...

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 Resin, resins and terpenes – in particular, tetrahydrocannabinol (THC), c ...

: the former is a

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

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

extract An extract (essence) 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 or absolutes or dried and powdered. The aromatic principles of ma ...

of dried female hemp flowers (

marijuana Cannabis (), commonly known as marijuana (), weed, pot, and ganja, List of slang names for cannabis, among other names, is a non-chemically uniform psychoactive drug from the ''Cannabis'' plant. Native to Central or South Asia, cannabis has ...

) or resin ( hashish). 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 combinations. Biochemical modifications s ...

s, and other

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

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,

esters In chemistry, an ester is a chemical compound, compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds c ...

, and the heterocyclic compounds indole and

skatole Skatole or 3-methylindole is an organic compound belonging to the indole family. It occurs naturally in the feces of mammals and birds and is the primary contributor to fecal odor. In low concentrations, it has a flowery smell and is found in sever ...

. 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. 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 Afghan 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 an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...

ester In chemistry, an ester is a compound derived from an acid (either organic or inorganic) in which the hydrogen atom (H) of at least one acidic hydroxyl group () of that acid is replaced by an organyl group (R). These compounds contain a distin ...

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 essential oil of citrus fruit peels. The (+)-isomer, occurring more commonly in nature as the fragrance of oranges, ...

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

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 combinations. Biochemical modifications s ...

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. 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 (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, 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.

References

Sources

* *

External links

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