Terpenes (pronounced
/ˈtɜrpiːn/ TUR-peen) are a large and varied class of
hydrocarbons, produced primarily by a wide variety of plants, particularly
conifers,
[1] though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their
osmeterium.
They are the major components of
resin, and of
turpentine produced from resin. The name "terpene" is derived from the word "
turpentine". In addition to their roles as end-products in many organisms, terpenes are major biosynthetic building blocks within nearly every living creature.
Steroids, for example, are derivatives of the triterpene
squalene.
When terpenes are modified chemically, such as by oxidation or rearrangement of the carbon skeleton, the resulting compounds are generally referred to as
terpenoids. Some authors will use the term terpene to include all terpenoids. Terpenoids are also known as
isoprenoids.
Terpenes and terpenoids are the primary constituents of the
essential oils of many types of plants and flowers. Essential oils are used widely as natural flavor additives for food, as fragrances in perfumery, and in traditional and alternative medicines such as
aromatherapy. Synthetic variations and derivatives of natural terpenes and terpenoids also greatly expand the variety of aromas used in perfumery and flavors used in food additives.
Vitamin A is an example of a terpene.
Terpenes are released by trees more actively in warmer weather, acting as a natural form of
cloud seeding. The clouds reflect sunlight, allowing the forest to regulate its temperature.
[2]