An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are generally extracted by distillation, often by using steam. Other processes include expression, solvent extraction, absolute oil extraction, resin tapping, wax embedding, and cold pressing. The steam passes through the plant material, vaporizing the volatile compounds. The vapors flow through a refrigerant, where they condense back to liquid, which is then collected in the receiving product. The condensed water is referred to as a hydrosol, herbal distillate, or plant water essence, which may be sold as another fragrant product. [1]
Essential oils are a rich source of phenolic compounds, flavonoids, tannins and other antioxidant compounds, which are the most important natur antioxidants. Today, a large group of plants and their extract have been considered as natural resources with antioxidant properties. Essential oils are used in the manufacture of perfumes, cosmetics, soaps and shampoos, air fresheners, hygiene products, and other products, also essential oils are used to flavorfood and beverages, and to add aromas to household cleaning products. [2]
Essential oils determine their therapeutic effect in the body of humans, therefore, they are classified into certain groups according to their radius. A essential oil has no definite effect and its spectrum may be increased or reduced. Means that a plant may be effective in the treatment of several diseases and on the contrary, to enhance their therapeutic effect, a mixture of several plants is often prepared to multiply their effect. [3]
[1] Catherine Regnault-Roger1, Charles Vincent2, and John Thor Arnason3, Essential Oils in Insect Control: Low-Risk Products in a High-Stakes World, Vol. 57:405-424 (Volume publication date January 2012)
[2] K. Husnu Can Baser, Gerhard Buchbauer, Handbook of Essential Oils: Science, Technology, and Applications, CRC Press, 2009 M12 28 – 991 pages.
[3] Gilman, A. G.; Rall, T. W.; Nies, Alan S.; Taylor, Palmer, eds. (1990). Goodman & Gilman’s the Pharmacological Basis of Therapeutics. New York: Pergamum. ISBN 978-0-08-040296-3.