Monoterpenes

Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. They may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those with oxygen-containing functional groups, are referred to as monoterpenoids.

Structure and Biosynthesis

Monoterpenes are derived biosynthetically from units of isopentenyl pyrophosphate, which is formed from acetyl-CoA via the intermediacy of mevalonic acid in the mevalonate pathway. The addition of three isopentenyl pyrophosphate molecules in the Non-mevalonate pathway or the addition of two isopentenyl pyrophosphate molecules in the mevalonate pathway results in the formation of monoterpenes.

Types of Monoterpenes

There are three major types of monoterpenes: acyclic, monocyclic, and bicyclic.

• Acyclic Monoterpenes do not contain a ring in their structures. Examples include myrcene and ocimene.
• Monocyclic Monoterpenes contain one ring in their structures. Examples include limonene and terpinene.
• Bicyclic Monoterpenes contain two rings in their structures. Examples include pinene and camphene.

Uses and Applications

Monoterpenes are often used in perfumery and in aromatherapy due to their pleasant scents. They are also used in traditional and alternative medicines such as aromatherapy for their supposed health benefits. In addition, they have been studied for their potential use in cancer treatment.

See Also

• Terpene
• Sesquiterpene
• Diterpene
• Triterpene
• Tetraprenyl-beta-curcumene synthase
• Geranyl pyrophosphate