Monoterpenes

Monoterpenes are aliphatic mono-, di- or tricyclic terpenes, which are formally formed from 2 isoprene units (C10H16). Monoterpenes are mostly volatile natural substances. Together with other terpenes they are the main ingredients (about 90%) of essential oils (Olea aetherea), which are obtained by squeezing, distillation with steam, oil extraction processes or solvent extraction. Monoterpenes are used in large quantities in the pharmaceutical, food, perfume and paint industries. They are biosynthesized from geranyl pyrophosphate (isoprenoids - see terpenes below).

Acyclic monoterpenes are formed by hydrolysis of the phosphate bond. In various further chemical steps monoterpene alcohols, monoterpene aldehydes and ketones as well as mono- and bicyclic monoterpenes are formed by cyclization reactions.

Examples of monoterpenes: linalool, citronellol, eugenol, terpineol, menthol, terpinene, sabinene, limonene, alpha and beta pinene, camphor, myrtenol and others.

Monoterpenes have analgesic, antioxidant and anti-inflammatory effects to varying degrees. Some monoterpenes play a role as pheromones in animal organisms.
Monoterpenes have a great allergological importance.

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3. Oz M et al(2015) Effects of monoterpenes on ionchannels of excitable cells. Pharmacol Ther 152:83-97.