Linalool – C10H18O – Uses, Health Benefits, Sources and Toxicity Information

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Linalool is the chief volatile compound that lends a characteristic smell to lavender. However, the smell of any fragrant plant or spice or even a food item is not merely owing to any one particular constituent, but is a result of the relative proportion of many aromatic compounds. Linalool, though most commonly associated with lavender is also found is variable proportions in a large number of plants and herbs and some fruits as well. 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.  



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 aromas of other citrus plants, mainly bitter orange (also called petit-grain) but also orange and bergamot.  

Linalool – C10H18O
Linalool – C10H18O (Image:Shutterstock)

Chemically, linalool is a 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, one called 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 the fact that they have 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 which 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 coriandrol. 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 is a result of 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 mildly reduce blood pressure. [3] 
  • Anti-inflammatory – It has been shown to reduce systemic inflammation which leads to swelling (edema). [4] 
  • Anti-nociceptive – S-Linalool has shown ability to reduce pain relayed by the nerves when it is due to chronic inflammatory conditions. [5] 
  • Anti-Alzheimer’s – studies conducted on rats have demonstrated ability of linalool (when given orally) to reduce the signs of alzheimer’s disease (by improving memory as well as 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 really powerful 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 effects. 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 is able to 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 strong skin irritation if applied topically without diluting.  

Linalool is easily available online for both industrial purposes (manufacturers of soaps, scent blends, toiletries and cosmetic products) and also for the household consumers. We can easily get 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 actually be so strong in aroma that they can overdo what one would be intending to achieve. For example, it may lower blood pressure to dangerously low levels. Therefore, one should rather opt for much lower purity of linalool and 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 house-flies, 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 of the world 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 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 just use a perfume which contains linalool. Its like killing two birds with one stone. Some people love to dip a bracelet or a band 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 is 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 purest linalool for developing new perfumes take adequate precautions like laboratory glasses and gas masks. Some people who purchase pure linalool have been using it to mix it in other oils and create their own 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.  A lot of factors, like solubility, compatibility, stability under heat, oxidation and possibility of chemical reactions needs to be taken into account when mixing linalool into other essential oils.   

Sources

There are actually two ways of making linalool. One way is that nature makes the linalool, we just distillate the plant to get its essential oil and separate out 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 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 contain 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 (ocimum basilicum)  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 as 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 flavored teas are one of the best ways of availing the health benefits of linalool. Similarly, certain red and white ones, especially from regions that contain plants that are rich in linalool give off a hint of its aroma. Wine connoisseurs would know the importance of a distinctive aroma 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 people who are sensitive (not allergic) to it 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 in a cool temperature and away from kitchen items. It should never be kept in an aluminum 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 turn out to be 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.  

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

  1. Linalool – Advances in Phytomedicine, 2002, Elaine Elisabetsky.
  2. Tripathi A.K. and Mishra S.  Ecofriendly pest management for food security. Plant Monoterpenoids – Prospective Pesticides.  
  3. Cardiovascular effects induced by linalool in normotensive and hypertensive rats. Anjos P.J. et al. Z Naturforsch C. 
  4. Anti-inflammatory activity of linalool and linalyl acetate constituents of essential oils. Peana A.T. et al. Phytomedicine.  
  5. The antinociceptive effect of (-)-linalool in models of chronic inflammatory and neuropathic hypersensitivity in mice. Batista P.A. J Pain. 
  6. Linalool reverses neuropathological and behavioral impairments in old triple transgenic Alzheimer’s mice. Maria S.A. et al. Neuropharmacology.  
  7. 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.  
  8. Chemical Background – Linalool, NIH.         

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