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 ar ...

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 mechanism ...

s and spice 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 In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, ...

, a volatile oil component, an

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ...

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

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...

ic forms are found in nature: (''S'')-linalool is found, for example, as a major constituent of the essential oils of

coriander Coriander (;

('' Coriandrum sativum'' L.), cymbopogon ('' Cymbopogon martini'' var. ''martinii''), and sweet orange ('' Citrus sinensis'') flowers. (''R'')-linalool is present in lavender ('' Lavandula officinalis''), 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-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 and other herbs),

Lauraceae Lauraceae, or the laurels, is a plant family that includes the true laurel and its closest relatives. This family comprises about 2850 known species in about 45 genera worldwide (Christenhusz & Byng 2016 ). They are dicotyledons, and occur m ...

( laurels,

cinnamon Cinnamon is a spice obtained from the inner bark of several tree species from the genus '' Cinnamomum''. Cinnamon is used mainly as an aromatic condiment and flavouring additive in a wide variety of cuisines, sweet and savoury dishes, brea ...

, 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 3 ...

and other plants, from

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred 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, g ...

zones. * '' Lavandula'' * '' Cinnamomum tamala'' * '' Cannabis sativa'' * '' Basil'' * ''

Solidago ''Solidago'', commonly called goldenrods, is a genus of about 100 to 120''Solidago''.
F ...

'' * '' Artemisia vulgaris'' (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

In higher plants 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 majority Here is an adverb that means "in, on, or at this place". It may also refer to: Software * Here Technologies, a mapping company * Here WeGo (formerly Here Maps), a mobile app and map website by Here Television * Here TV (formerly "here!"), a TV ...

of 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 An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense ...

and flavor properties. Its odor is similar to floral, spicy wood, somewhat resembling

French lavender French lavender may refer to at least two species of plants in the genus ''Lavandula'': *''Lavandula dentata ''Lavandula dentata'', ''Lavanda de la brecha (Spain)'', fringed lavender or French lavender, is a species of flowering plant in the ...

plants,

bergamot oil Bergamot essential oil is a cold-pressed essential oil produced by cells inside the rind of a bergamot orange fruit. It is a common flavoring and top note in perfumes. The scent of bergamot essential oil is similar to a sweet light orange peel oi ...

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 perfumed 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 used ...

detergent A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are m ...

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 th ...

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 oil An essential oil is a concentrated hydrophobic liqu ...

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