This is volatile, with a strong characteristic odor and flavor, oily, water-insoluble, substantially colorless or lightly colored liquid. Unlike these fats they do not leave grease stains on paper because are evaporated already at room temperature. Essential oils are formed exclusively in plants, but have extremely strong physiological and pharmacological properties. In pure form, they are obtained by steam distillation, absorbing by fats, sometimes are squeezed under pressure or extracted by liquid carbon dioxide and other solvents. In herbal medicine, they are used not only purified, for example, for inhalation a device “Fitton”, but in tinctures that are made on alcohol, given the insolubility of terpenes in water or in steam as, say, it is done with sage leaves or eucalyptus for rinsing. Essential oils are soluble by alcohol, ether or fats and in such forms are widely used in perfumery. Essential oils are also important in the food industry - in herbs and spices.
Essential oils are distinguished and called after the plants from which they are derived: peppermint, lavender, rose and so on. Each of them is a mixture of several or more individual chemical compounds - terpenes and their derivatives. Terpenes - hydrocarbons i.e. consist only of C and H and characterized by the fact that in the molecules there are a lot of unsaturated carbon bonds, which cause a high chemical activity of these substances. There are monoterpenes, sesquiterpenes and diterpenes (terpenes with a large number of condensed molecules form resin and rubber). Carbohydrate may replace one of the hydrogens on any other molecular group, and thus acquire a new quality.
Examples of monoterpenes: mirtsin as hydrocarbons and otsimin, much as their derivatives, aldehydes and ketones are found in the composition of many essential oils. These are Citronellol, citral, limonene, a-pinene, menthol, myrtenol, borneol, camphor, verbenone and piperitone.
Sesquiterpene is in a sandalwood tree (B-santalin) in the eucalyptus oil - kadinol and eudesmol. Diterpenes are rare, but known, camphor, phytol (part of the chlorophyll), abietic acid.
In plants, essential oils, contained in special cells - receptacles, come out from there after a destruction or when heated.
The physiological effects of essential oils are fulfilled by different means. In direct contact with their skin caused by irritation, increased blood flow to this place (hyperemia), which is used in compression and rinsing with ether-oleaginous steaming. At high concentrations or prolonged exposure may cause skin burns. Dissolved in fats (Vietnamese balm "Golden Star") essential oils on the skin locally inhibit inflammation (antiphlogiston effect). Through the skin, they can enter the bloodstream and spread throughout the body. But definitely their inhalation: facilitates expectoration.
Getting in the mouth, and stimulating nerve endings essential oils act through the nervous system to the stomach, causing increased secretion of gastric juice secretion of the pancreas and bile, that is, those juices and enzymes, mainly engage the process of digestion and assimilation of food. Thus they act on appetite, normal, healthy food intake, and are reached by flavors to dishes, canned goods, etc. (dill, parsley, cumin, coriander and many others).
Essential oils also act on the urinary organs. Attribute this to the fact that drugs with thyme or pure thymol (from thyme oil) or other diuretics medications with essential oils dilates blood vessels by filtering system of the kidneys (nephrons) and make them more easily permeable. Important remedy with such effect is “fruits” of juniper, parsley roots, seeds or leaves of lovage.
So, in general, essential oils are important medications for cleaning the body from the sputum, urine and other waste, they discover an antispasmodic effect on the muscles of the intestine, accelerating digestion. They also improve the flow of milk in nursing mothers. Some essential oils such as peppermint have a clear choleretic action and are used for inflammation of the gall bladder and jaundice.
However, essential oils cannot be abused. They can cause considerable damage during menstruation and pregnancy due to flushing (to abortion).
Finally, essential oils have a clear effect on the static bacteria, especially fat-like substance impregnated with the shell and therefore very resistant to other disinfectants (Staphylococcus aureus). Fumigation essential oils are used for disinfection of premises, clothing and leather. Since essential oils generally have a pleasant odor to humans, such action contributes to improving health. The characteristic essential oil plants: valerian, fennel, dill, coriander, lavender, lovage, lemon balm, muskatnik, mint, parsley, rosemary, sage, thyme, oregano, juniper, sage, lemon, orange, rose.