Monoterpene

Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or rearranged skeletons, are referred to as monoterpenoids. Monoterpenes are the major components in plant essential oils.

Biosynthesis

Monoterpenes are derived biosynthetically from units of isopentenyl pyrophosphate, which is formed from acetyl-CoA via the intermediacy of mevalonic acid in the HMG-CoA reductase pathway. An alternative, the MEP pathway, utilizes pyruvate and glyceraldehyde 3-phosphate as substrates. The cyclization of a linear isoprene and the formation and modification of its double bonds is catalyzed by enzymes called terpene synthase.

Uses

Monoterpenes are often used in the perfume industry due to their pleasant scents. They are also used in medicine for their antibacterial, antiviral, and anti-inflammatory properties. Some monoterpenes are known to have insecticidal activity.

Examples

Examples of monoterpenes and monoterpenoids include myrcene, limonene, terpinene, ocimene, pinene, menthol, camphor, geraniol, and thujone.

See also

• Sesquiterpene
• Diterpene
• Triterpene
• Tetraterpene