Linalool is the chief volatile compound that lends a characteristic smell to lavender. However, the scent of any fragrant plant or spice or even a food item is not merely owing to any one particular constituent. Still, it is a result of the relative proportion of many aromatic compounds. Linalool, though most commonly associated with lavender, is also found in variable proportions in many plants and herbs and some fruits. Because of its fragrance, it is used in perfumes, deodorants, soaps and oil blends. It has a particular sedative and calming effect on the body and the mind, and it is used in aromatic products and in candles to reduce stress and bring about sleep.
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Chemical Nature
Linalool is a fragrant compound that is volatile. That means, even at room temperature, lavender keeps emitting some linalool as a part of its scent. The characteristic aroma of linalool is a concoction of lemon mixed with a smell of woods and faint aroma of other citrus plants, mainly bitter orange (also called petit-grain) and orange and bergamot.
Chemically, linalool is terpene alcohol. This class of compounds emerged as an evolutionary need of plants to protect themselves from their harsh environments in the tumultuous ages of earth’s geological past, like the Jurassic and the Cretaceous. Large trees like pines developed strategies to produce and secrete aromatic, resinous secretions, whose aromas would help them in one way or another, for example, keeping a pest away.
When we delve deeper into its chemistry, we find that linalool exists in two different forms: the R-linalool and the other called S-linalool (with a capital R and a capital S, that’s very important). These two are optically active isomers of one another and are called enantiomers. This matter is of significance to us because optically active compounds have slight differences in their chemical properties. Hence, R-linalool is not the same as S-linalool, which can be easily proved by having different aromas. Since both of these forms exist in nature, we need to be aware of their sources and different properties.
The more common form of linalool is R-linalool, and this is the one that is predominant in lavender. It goes by another name as well, licareol. Its aroma is woodier and more floral than the other one.
S-linalool is present in good strength in the essential oil of coriander; hence it is also called coriander. Its aroma is fruitier, more citrus-like but still doesn’t lose too much of its original lavender-like aroma.
Therapeutic Properties and Health Benefits
Linalool is responsible for quite a lot of lavender and lavender oil’s calming effects on the mind. Here is an exhaustive list of its medicinal effects.
- Anticonvulsant – This results from its powerful sedative effect because it relaxes the central nervous system (CNS). [1]
- Insecticide against specific insects viz. Fruit flies, ticks, fleas (especially cat fleas), housefly and cockroaches. [2]
- Hypotensive – has been proven to reduce blood pressure mildly. [3]
- Anti-inflammatory – It has been shown to reduce systemic inflammation, which leads to swelling (oedema). [4]
- Anti-nociceptive – S-Linalool has shown the ability to reduce pain relayed by the nerves due to chronic inflammatory conditions. [5]
- Anti-Alzheimer’s – studies conducted on rats have demonstrated the ability of linalool (when given orally) to reduce the signs of Alzheimer’s disease (by improving memory and cognition) through various mechanisms. [6]
- Anxiolytic – It reduces anxiety and nervousness and would help people to relax better. [6]
- Emotive – people who have been administered linalool explain that it helps them contemplate and understand their emotions better. This is a potent therapeutic effect of linalool. [6]
Let’s pause and analyze these therapeutic effects for a second. Linalool’s ability to calm us by dulling the central nervous system could be at the root of its other products. A suppression of hyperactivity induces a sense of calm and poise. Our worries are reduced, and that too plays a role in reducing elevated blood pressure. A calm mind can think better and concentrate better.
- Anti-cancerous against leukaemia and cervical cancer. [7]
How to use Linalool at Home
It is generally advised to use essential oils of specific plants for achieving desired objectives. Linalool is just one compound out of a myriad of constituents in many aromatic plants. It is much stronger than complete essential oils. However, it can be used directly in vaporizers around the house if you use the right strength and your body can tolerate it. Linalool can cause respiratory distress in some people and intense skin irritation if applied topically without diluting.
Linalool is readily available online for industrial purposes (manufacturers of soaps, scent blends, toiletries and cosmetic products) and household consumers. We can easily get a linalool with 97% purity. It is to be warned that such strengths of linalool are suitable only for industries and are quite dangerous in the household, especially if there are children and pets. Such powerful purity of linalool may be so strong in an aroma that they can overdo what one intends to achieve. For example, it may lower blood pressure to dangerously low levels. Therefore, one should instead opt for a much lower purity of linalool. The best would be to go for complete essential oils, like lavender or coriander, to get a more complex and richer aroma.
Most scented candles contain only about 5% of the candle’s weight as aromatics. A 5% linalool scented candle is ideal for keeping away houseflies, ticks and fleas. There is some anecdotal evidence in research to suggest that linalool also repels certain species of mosquito. The scented candle would work against mosquitoes as well. This is especially helpful in tropical, hot and humid areas where flies and mosquitoes are a seasonal nuisance. Well, they are more than a nuisance. Flies are the major vectors for causing many food and water-borne diseases. We can safeguard ourselves from many such infections by simply driving away from the carrier insects.
A few drops of a 5 to 10% solution of linalool in some base oil (like coconut oil) can also be applied directly on the skin to ward off insects. A better way is to use a perfume which contains linalool. It’s like killing two birds with one stone. Some people love to dip a bracelet or a brand into a linalool-based dip and then wear it. These dips are often available as household insecticides and do not have linalool more than 5%. The second method doesn’t smell as strong as a perfume but still gets the job done.
For keeping ticks and fleas off our beloved dogs and cats, a spray with less than 1% of it as linalool is sufficient. Higher amounts of linalool are not tolerated well by dogs and cats. Linalool is especially dangerous to rabbits. So, if you have rabbits at home, avoid using linalool nearby.
It is known that perfume designers and expert chemists who use the purest linalool for developing new perfumes take adequate precautions like laboratory glasses and gas masks. Some people who purchase pure linalool use it to mix it in other oils and create their blends and customized aromas at home. The suitability of this has not been evaluated. This task must be left to those with specific knowledge of these natural chemicals. Many factors, like solubility, compatibility, stability under heat, oxidation, and the possibility of chemical reactions, need to be taken into account when mixing linalool into other essential oils.
Sources
There are two ways of making linalool. One way is that nature makes the linalool; we distillate the plant to get its essential oil and separate the linalool from the other constituents. This is the natural linalool.
Another way to manufacture is the chemical one. Reactions used in making vitamin E also yield linalool at some intermediate stage. This linalool is purely synthetic.
There are more than two hundred plant sources of natural linalool. But it is mainly extracted from these two plants – Bois-de-Rose and Ho-leaf. Bois-de-rose oil is the essential oil obtained from the bark of a redwood tree. It can contain upto 95% linalool. Ho-leaf essential oil is the oil extracted from the bark and leaves of the evergreen plant Cinnamomum camphora. Plants that have a significant quantity of linalool are mentioned below.
| Essential oil | Percentage of linalool |
| Ho leaf | 80-90 |
| Bois-de-rose | 65-90 |
| coriander | 60-80 |
| Linaloe | 30-70 |
| Sweet basil (ocimumbasilicum) | 30-50 |
| Lavandin (same family as lavender) | 30-40 |
| Lavender | 20-50 |
| Petit grain | 20-30 |
Source: 8
Other plants that contain linalool are
- Indian bay leaf (commonly called tejpatta) – Cinnamomum Tamala.
- Artemisia vulgaris, which is commonly known as mugwort.
- Plants of the mint family
- Plants of the citrus family
- Some species of cannabis, mainly cannabis sativa and cannabis indica.
- Some evergreen trees like laurels and rosewoods.
Common citrus fruits, many varieties of trees, some natural resins and even certain wines and teas contain linalool. Some tea makers add a touch of food-grade linalool to teas, mainly earl grey and black. These flavoured teas are one of the best ways of availing the health benefits of linalool. Similarly, certain red and white ones, especially from regions containing plants rich in linalool, give off a hint of its aroma. Wine connoisseurs would know the importance of a distinctive fragrance in a wine from a specific region.
Safety and Toxicity Issues
Linalool is commonly labelled as a skin irritant, an eye irritant and a respiratory irritant. This means that few sensitive (not allergic) people would develop health issues, like mild breathing discomfort. It is not known to cause sharp allergic reactions. Some people may break out into allergic dermatitis.
Linalool’s chemical structure is such that it is prone to oxidation. Its oxidized form is quite toxic to humans. Thus, linalool should be kept at a cool temperature and away from kitchen items. It should never be kept in an aluminium bottle.
So, it is relatively safe to use it in the short term. However, its long-term effects on health have not yet been evaluated. There are conflicting opinions and conjectures in the medical community on whether linalool could be a carcinogen when used in the long term. However, since linalool is present in small amounts in many of the fragrant products that we see, it is quite unlikely that linalool would have a direct carcinogenic role.
Also Read – Quinoa Oil
Buying Guide
The best linalool is the natural one, sourced from organic, GM-free plants that have not been sprayed with pesticides. Many of the products in the market are a 50:50 mix of the R form and the S form. Such a mixture is called a racemic mixture (chemistry terminology). These are not as good as pure R or pure S linalool in terms of aroma. Pure ones are called enantiomers. So, before purchasing, be on the lookout for this. Pure R linalool (or S linalool) is going to be much costlier than the mixture.
References
- Linalool – Advances in Phytomedicine, 2002, Elaine Elisabetsky.
- Tripathi A.K. and Mishra S. Eco-friendly pest management for food security. Plant Monoterpenoids – Prospective Pesticides.
- Cardiovascular effects induced by linalool in normotensive and hypertensive rats. Anjos P.J. et al. Z Naturforsch C.
- Anti-inflammatory activity of linalool and linalyl acetate constituents of essential oils. Peana A.T. et al. Phytomedicine.
- The antinociceptive effect of (-)-linalool in models of chronic inflammatory and neuropathic hypersensitivity in mice. Batista P.A. J Pain.
- Linalool reverses neuropathological and behavioural impairments in old triple transgenic Alzheimer’s mice. Maria S.A. et al. Neuropharmacology.
- Linalool Induces Cell Cycle Arrest and Apoptosis in Leukemia Cells and Cervical Cancer Cells through CDKIs. Mei – Yin Chang et al. International Journal of Molecular Sciences.
- Chemical Background – Linalool, NIH.
