Turpentine and Terpenoids

Terpenoids is a subclass of the prenyllipids (terpenes, preylquinones, and sterols), represent the oldest group of small molecular products synthesized by plants and are probably the most widespread the oldest group of small molecular products synthesized by plants and are probably the most widespread group of natural products.

Terpenoids can be described as modified terpenes, where methyl groups are moved or removed, or oxygen atoms added. Inversely, some authors use the term "terpenes" more broadly, to include the terpenoids

During the 19th century, chemical works on turpentine led to name "terpene" the hydrocarbons with the general formula C10H16 found in that complex plant product. These terpenes are frequently found in plant essential oils which contain the "Quinta essentia", the plant fragrance

They are universally present in small amounts in living organisms, where they play numerous vital roles in plant physiology as well as important functions in all cellular membranes. The various functions of terpene natural products in the natural world have been reviewed. On the other hand, they are also accumulated in many cases, and it is shown that the extraordinary variety they then display can be due to ecological factors playing an evolutionary role.

Terpenoids are extraordinarily diverse but they all originate through the condensation of the universal phosphorylated derivative of hemiterpene, isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) giving geranyl pyrophosphate (GPP).

Terpenes history spans various civilizations. As they are largely found in essential oils, they were used in the Ancient Egypt for various religions aims. Camphor was introduced in Europe from the East by the Arabs around the 11th century.

The process of obtaining plant essential oils by fatty extraction was known by the early Middle Ages. In the 12th century, Arnaud de Villanosa described distillation of oils from rosemary and sage. He made an "oleum mirabile" from oils of turpentine and rosemary. It is noticeable that some 60 oils were described in the Nuremberg edition of "Dispensatorium valerii cordi" written in 1592.

Analyses of oils of turpentine were made in 1818 by JJ Houston de la Billardière. Dumas proposed in 1866 the name "terpene", derived from turpentine, instead of camphor for crystalline oxygenated substances extracted from essential oils. In 1887, Wallach O proposed that one isoprenic unit of 5 carbon atoms (C5H8) is always present in the molecule of terpenes (Justus Lieb Ann Chem 1887, 238, 78).

The structure of camphor was established by Bredt in 1893, that of pinene by Wagner in 1894 and that of citral by Tiemann in 1895. b-Carotene was isolated in 1837 by Wackenrodder from carrots, and its correct molecular form was determined in 1907 by Willstätter.

http://www.cyberlipid.org/simple/simp0004.htm

Terpene is any of a large and varied class of hydrocarbons, with the molecular formula (C5H8)n, that are produced by a wide variety of plants, such as conifers. Terpenes also are produced by some other living organisms, such as swallowtail butterflies, which emit terpenes from their osmeterium, and a fungus isolated from St. John's Wort. The term "terpene" at times is used broadly to also include the terpenoids, which are terpenes that have been chemically modified, such as through oxidation.

Terpenes are natural products derived from plants that have medicinal properties and biological activity. Terpenes may be found in cleaning products, rubefacients, aromatherapy, and various topical preparations. Terpenes may exist as hydrocarbons or have oxygen-containing compounds such as ketone or aldehyde groups (terpenoids).

http://emedicine.medscape.com/article/818675-overview