Terpineols are monocyclic monoterpene tertiary alcohols and can be found in 150 plants, including flowers, fruits, and spices such as apples, basil, limes, lilac, grapefruit, rosemary, eucalyptus, and pine trees. There are five common isomers of terpineols, alpha-, beta-, gamma-, delta- and terpinen-4-ol, of which α-terpineol and its isomer terpinen-4-ol are the most common terpineols found in nature.
Both α-Terpineol and Terpineol-4-ol are the most important commercial products and they occur in a large number of essential oils. On the other hand, β-, γ- and δ-terpineols do not occur very often in nature. Terpineols, especially the most commonly used compounds as α-Terpineol and Terpineol-4-on, exert a wide range of different biological actions on humans, animals, and also plants. They are not only popular fragrance ingredients used in perfumes, cosmetics, and household cleaning products, but also used to flavor foods and beverages. They also possess various important biological and medicinal properties.
α-Terpineol plays an important role in the industrial field. Because of its pleasant odor similar to lilac, α-Terpineol is widely used in the manufacturing of cosmetics, soaps, perfumes, antiseptic agents and is considered one of the most frequently used fragrance compounds. Its acetate and other simple esters of α-Terpineol are also used in perfumes and aromatic scents. Therefore, the most important reaction for the fragrance industry is its esterification particularly the acetylation of terpinyl acetate. In addition, α-Terpineol possesses a wide range of biological applications as it exhibits an antihypertensive and antiproliferative effect on human erythroleukemic cells, as well as anti-inflammatory properties , as it was found to be a potent inhibitor of superoxide production. And many studies have reported that α-Terpineol has an obvious anticancer effect.
Another important biological activit of α-Terpineol was its promising effect as a chemical skin penetration enhancer, currently believed to improve the solubility within the stratum corneum (SC) or to increase the lipid fluidity of the intracellular bilayers. In addition, the insecticidal activity of α-Terpineol attracted the interest of many scientists. Therefore, it is suggested that α-Terpineol may be a potential agent for the development into natural insecticides or fumigants, as well as repellents for control of insects.
Consequently, α-Terpineol has exhibited a potential satisfaction in certain activities due to its usage in pharmaceutical and agricultural industries. Encouraging results from these wide range of biological activities show that α-Terpineol is very promising candidate in pharmaceutical and agricultural applications.