Linalool

Linalool is a naturally occurring monoterpene alcohol found in hundreds of flowering plants and spices, widely recognised for its floral, slightly spicy aroma and its role as a common constituent of essential oils.

Linalool (CAS 78-70-6) is a chiral monoterpenoid alcohol with the molecular formula C₁₀H₁₈O. It occurs as two enantiomers: (R)-(−)-linalool (also called licareol), which predominates in coriander and certain rosewood species, and (S)-(+)-linalool (also called coriandrol), more abundant in lavender, basil, and sweet orange. Both forms are colourless to pale-yellow liquids at room temperature and are characterised by a soft floral-woody scent with faint citrus undertones, making linalool one of the most commercially significant aroma compounds in the fragrance and flavour industries.

In plants, linalool is biosynthesised via the methylerythritol phosphate (MEP) pathway in plastids, typically from geranyl pyrophosphate (GPP) through the action of linalool synthase enzymes. It is found across a broad range of botanical families, including Lamiaceae (lavender, mint, basil), Apiaceae (coriander, angelica), Myrtaceae (tea tree, eucalyptus), and Cannabaceae (hemp, cannabis). In cannabis and hemp specifically, linalool is a minor but frequently detected terpene component of the plant's volatile fraction.

Preclinical laboratory studies , conducted primarily in cell cultures and rodent models , have examined linalool's interactions with various receptor systems, including GABA-A receptors and adenosine pathways. These findings are preliminary; the biological relevance of such mechanisms in humans has not been established through adequate clinical trials, and no conclusions about therapeutic effect should be drawn from them. Regulatory bodies including the Therapeutic Goods Administration (TGA) have not approved linalool as an active therapeutic ingredient for any indication.

Linalool is classified as Generally Recognised As Safe (GRAS) as a flavouring agent by relevant food-safety authorities when used at typical culinary concentrations. At higher dermal concentrations, oxidised forms can act as contact allergens, and the International Fragrance Association (IFRA) publishes usage guidelines accordingly. In Australia, linalool present in therapeutic goods or listed medicines falls under the TGA's assessment framework for excipients and active ingredients, governed by the Therapeutic Goods Act 1989 (Cth) and associated instruments.

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