Linalool is a terpene alcohol that occurs naturally and is present in several flowers as well as spice plants. This natural chemical has several different commercial applications – most of which are owing to its pleasing aroma. This substance has a floral scent with a tinge of tang.
The color of this natural chemical substance varies from colorless to very light yellow. It is available in a liquid form and has a floral aroma akin to that of French lavender and bergamot oil. Linalool is extensively employed for making flavours and fragrances. It is also widely used in cosmetics as well as personal care items. Various aftershave lotions, bubble baths, bath products, cleansing products, lipsticks, perfumes, moisturizers, colognes, hair care products, skin care products, shampoos and suntan products often contain linalool formulations.
A naturally occurring aromatic chemical, linalool is produced by an assortment of plants like birch trees, mint, citrus fruits, cinnamon plants. Apart from the naturally produced linalool, it can also be made synthetically. This chemical is among the terpene alcohols that are extensively spread throughout the plant kingdom. This substance has potent consequences on the nervous system and, hence, is widely employed by herbologists and aroma therapists in the form of a sedative, a local anaesthetic as well as a spasmolytic.
More than 200 plant species produce linalool. Most of these species belong to the Lamiaceae, which include mints and other aromatic herbs; Lauraceae, which include rosewood, cinnamon and laurels, and Rutaceae which includes citrus fruits. In addition, birch trees as well as other plant species from the tropical to boreal zone. It has been found that some fungi also contain linalool.
As much as 60 percent to 80 percent perfumed hygiene products as well as cleaning agents such as lotions, shampoos, soaps and detergents use linalool as an active ingredient.
In fact, linalool is among the most significant chemicals for the flavour and perfume industries and it is present in copious amounts in many plant species. As linalool is a key intermediate in manufacturing vitamin E, special processors have been developed for the purpose. These processors are useful for large-scale production of vitamin E using linalool.
Aside from the above uses, linalool is also employed by pest control professionals in the form of an insecticide for flea, cockroaches and fruit fly.
A number of mosquito repellent products also use linalool. However, the U.S. Environmental Protection Agency (EPA) states that a first round screen of labels items enclosing linalool as the only active element hints that the efficiency records file available with the agency may possibly not endorse specific claims regarding to the mosquito repellent property.
Interestingly, linalool has shown the potential to be used as a medication to treat leukemia. Among various substances that were examined, it was found that linalool had the most potent action against the histiocytic lymphoma cells. Similar to limonene, unadulterated linalool too possesses anti-carcinogenic actions.
In fact, several scientific studies have been undertaken to examine the potential health benefits of linalool. Most of these researches explored the anti-stress (anxiolytic) actions of linalool. Inhaling this plant compound, which has been extracted from its natural essential oils, results in diminished aggressive behaviour, reduces stress response and, at the same time, improves the quality of sleep.
American University of Beirut researchers are focusing on linalool, a particular natural element of several universal essential oils. In fact, linalool forms the sweetness of several essential oils and perhaps lavender is the most well-accepted oil containing linalool. Nevertheless, this natural compound is present in several other plant species. C.T. (or chemo-type) is the name of the thyme essential oil chemo-types linalool. In other words, this denoted that the specific thyme variety possesses the linalool molecules in an elevated percentage.
Linalool has a particular property and that is it can undergo cyclization very easily. During the initial stages of studies undertaken on linalool, it was discovered that this naturally occurring plant compound can be converted into nerol and geraniol by dilute sulfuric acid as well as concentrated formic acid. In addition, these two acids can also convert linalool into alpha terpin hydrate.
In early days, linalool was only obtained from natural resources. This substance was isolated from other constituents of an essential oil by means of undertaking cautious fractional distillation via efficient columns.
Earlier, it was possible to prepare synthetic linalool only by employing a method explained in 1919 by Ruzicka and Fornasis. In fact, the linalool employed in academic studies as well as the commercial linalool was only acquired from natural resources.
These days another process has become imperative for mass production of linalool. This process is founded on pinene chemistry and has actually made several other terpene derivatives available. Ever since, newer technologies for extracting linalool in the form of super critical fluids would become necessary for producing linalool from various plants species apart from rosewood for its precision in only hauling out the desirable matter at low temperatures.
Soap and detergent manufacturing units require large amounts of linalool, as it has been found that this substance not only helps in stabilizing the products, but also prevent them from non-discolouring. As discussed earlier, it is possible to convert linalool into citral, geraniol and terpineol and used for making citronellol, vitamin A, ionones, sesquiterpenes and farnesol.
In vitro, linalool dehydratase catalyzed two reactions in both directions subject to the thermodynamic driving forces, which include an isomerization of the main allylalcohol geraniol in the substance’s stereoisomer linalool and separation (secession) of water from the tertiary (formed by replacing three atoms) alcohol linalool to the subsequent acyclic monoterpene myrcene.
Citrus are an excellent resource of linalool. The juice industry in Brazil produces essential oil from the citrus fruit peels as a by-product and, hence, it is available at extremely low prices. However, their linalool content is of inferior quality.
Similar to geraniol, usually linalool is also an extremely stable product that pursues broad economic trends. However, the pricing of linalool has reduced mainly owing to the decreased prices for the compound’s main feedstock – crude sulfate turpentine.
These days, the cosmetic industry seems to be more and more interested in several different and frequently very particular essential oils of many of these having their origin in the tropical climatic regions of the globe. Hence, it is very difficult to characterize the specific demand situation for linalool.
Despites its several health benefits, the naturally occurring terpene alcohol chemical linalool should be used with caution. It has been found that linalool disintegrates gradually when it is exposed to oxygen. In such cases, it forms an oxidized by-product, which may result in allergic reactions like eczema in people vulnerable to this skin disorder. A study undertaken in Sweden found that about 5 percent to 7 percent patients who underwent patch testing were allergic to linalool’s oxidized form.
Linalool is present in several essential oils, counting rose, lavender, orange, rosewood as well as coriander. According to the Cosmetic Database, the major problem of using linalool is the hazard of developing skin irritations as well as allergic reactions. Similar to limonene, in its pure form, even linalool is not an allergen for the skin. Nevertheless, when linalool is oxidized, it may result in allergic reactions or sensitivity, especially when used in elevated concentrations.