Linalool () refers to two enantiomers of a naturally occurring

terpene Terpenes () are a class of natural products consisting of compounds with the formula (C5H8)n for n > 1. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes ...

alcohol found in many

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...

s and

spice A spice is a seed, fruit, root, bark, or other plant substance primarily used for flavoring or coloring food. Spices are distinguished from herbs, which are the leaves, flowers, or stems of plants used for flavoring or as a garnish. Spices a ...

plants. Linalool has multiple commercial applications, the majority of which are based on its pleasant scent (floral, with a touch of spiciness). A colorless oil, linalool is classified as an acyclic monoterpenoid. In plants, it is a metabolite, a volatile oil component, an antimicrobial agent, and an aroma compound. Linalool has uses in manufacturing of soaps, fragrances, food additives as flavors, household products, and insecticides.

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 of linalool are referred to as linalyl, e.g. linalyl pyrophosphate, an isomer of geranyl pyrophosphate. The word ''linalool'' is based on ''

linaloe ''Bursera'' is a genus with about 100 described species of flowering shrubs and trees varying in size up to high. It is the type genus for Burseraceae. The trees are native (often for many species endemic) to the Americas, from the southern Uni ...

'' (a type of wood) and the suffix '. In food manufacturing, it may be called ''coriandrol''.

Occurrence

Linalool Enantiomers Structural Formulae

Both enantiomeric forms are found in nature: (''S'')-linalool is found, for example, as a major constituent of the essential oils of coriander ('' Coriandrum sativum'' L.), cymbopogon ('' Cymbopogon martini'' var. ''martinii''), and sweet orange ('' Citrus sinensis'') flowers. (''R'')-linalool is present in lavender (''

Lavandula officinalis ''Lavandula angustifolia'', formerly ''L. officinalis'', is a flowering plant in the family Lamiaceae, native to the Mediterranean (Spain, France, Italy, Croatia etc.). Its common names include lavender, true lavender and English lavender (though ...

''), bay laurel (''Laurus nobilis''), and sweet basil (''Ocimum basilicum''), among others. Each enantiomer evokes distinct neural responses in humans, so each is classified as possessing distinct scents. (''S'')-(+)-Linalool is perceived as sweet, floral,

petitgrain Petitgrain () is an essential oil that is extracted from the leaves and green twigs of the bitter orange tree (''Citrus aurantium'' ssp. ''amara'') via steam distillation. It is also known as petitgrain bigarade. Etymology Petitgrain (Fr.: “ ...

-like (odor threshold 7.4 ppb) and the (''R'')-form as more woody and lavender-like (odor threshold 0.8 ppb). Over 200 species of plants produce linalool, notably from the families Lamiaceae (

mint MiNT is Now TOS (MiNT) is a free software alternative operating system kernel for the Atari ST system and its successors. It is a multi-tasking alternative to TOS and MagiC. Together with the free system components fVDI device drivers, XaAE ...

and other herbs), Lauraceae ( laurels, cinnamon, rosewood), and Rutaceae ( citrus fruits), but also

birch trees A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 to ...

and other plants, from tropical to

boreal climate The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, ge ...

zones. * '' Lavandula'' * ''

Cinnamomum tamala ''Cinnamomum tamala'', Indian bay leaf'','' also known as tejpat'', ''tejapatta'','' Malabar leaf, Indian bark, Indian cassia, or malabathrum, is a tree in the family Lauraceae that is native to India, Bangladesh, Nepal, Bhutan, and China. It c ...

'' * '' Cannabis sativa'' * '' Basil'' * '' Solidago'' * ''

Artemisia vulgaris ''Artemisia vulgaris'', the common mugwort, is a species of flowering plant in the daisy family Asteraceae. It is one of several species in the genus '' Artemisia'' commonly known as mugwort, although ''Artemisia vulgaris'' is the species most ...

'' (mugwort) * '' Humulus lupulus'' It was first synthesized in the laboratory of Leopold Ružička in 1919.Albert Eschenmoser: "Leopold Ruzicka - From the Isoprene Rule to the Question of Life's Origin" CHIMIA 44 (1990)

Biosynthesis

higher plants Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...

linalool is formed by rearrangement of geranyl pyrophosphate (GPP). With the aid of linalool synthase (LIS), water attacks to form the chiral center. LIS appears to show a limonene synthase-type catalysis through a simplified "metal-cofactor-binding domain here the majorityof the residues involved in substrate...binding rein the C-terminal part of the protein" suggesting stereoselectivity and the reasoning behind why some plants have varying levels of each enantiomer. Linalool_Biosynthesis

Odor and flavor

Linalool has complex odor and flavor properties. Its odor is similar to floral, spicy wood, somewhat resembling French lavender plants, bergamot oil or lily of the valley. It has a light, citrus-like flavor, sweet with a spicy tropical accent. Linalool is used as a scent in 60% to 80% of

perfume Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent ...

d hygiene products and cleaning agents, including

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...

s, detergents,

shampoo Shampoo () is a hair care product, typically in the form of a viscous liquid, that is used for cleaning hair. Less commonly, shampoo is available in solid bar format. Shampoo is used by applying it to wet hair, massaging the product into the ...

s, and lotions. It exhibits antimicrobial and antifungal properties.

Chemical derivatives

Linalool is hydrogenated to give dihydro- and tetrahydrolinalool, which are fragrances that are more resilient toward oxidants, as might be found in household cleaning products.

Linalyl acetate Linalyl acetate, an organic compound, is the acetate ester of linalool. phytochemical found in many flowers and spice plants. It is one of the principal components of the essential oils of bergamot and lavender. It often occurs together with l ...

, a popular scent, is produced by esterification of linalool (as well as occurring naturally). Isomerization of linalool gives

geraniol Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil, palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in w ...

and nerol.

Safety and potential toxicity

Linalool can be absorbed by inhalation of its aerosol and by oral intake or skin absorption, potentially causing irritation, pain and

allergic Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic der ...

reactions. Some 7% of people undergoing patch testing in Europe were found to be allergic to the oxidized form of linalool. The US Food and Drug Administration (FDA) lists linalool in the Code of Federal Regulations under substances generally recognized as safe, synthetic flavoring substances and adjuvants.

References

External links

Comprehensive data sheet
* {{Transient receptor potential channel modulators Flavors Tertiary alcohols Plant toxin insecticides Alkene derivatives Monoterpenes Perfume ingredients