Diterpene

Geranylgeranyl pyrophosphate, the starting material for the biosynthesis of diterpenes

Diterpenes are a class of chemical compounds composed of two terpene units with the molecular formula C₂₀H₃₂; they may also be thought of as consisting of four isoprene units. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important compounds such as retinol, retinal, and phytol. They are known to be antimicrobial and antiinflammatory.

Diterpene structures

Taxadiene: a tricyclic diterpene

As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present.

Number of rings	Examples
0	Phytane
1	Cembrene A
2	Sclarene, Labdane
3	Abietane, Taxadiene
4	Stemarene, Stemodene

Diterpenoids

Retinol: one of the animal forms of vitamin A

Phytol: usedin the biosynthesis of vitamin E and vitamin K1

Diterpenes are formally defined as being hydrocarbons and thus contain no heteroatoms. Functionalized structures should instead be called diterpenoids, although in scientific literature the two terms are often used interchangeably. Although a wide range of terpene structures exist few of them are biologically significant, by contrast diterpenoids possess a rich pharmacology and include important compounds such as retinol and phytol.

Taxanes

Taxanes are class of diterpenoids featuring a taxadiene core. They are produced by plants of the genus Taxus (yew trees) and are widely used as chemotherapy agents.

See also

• monoterpene
• sesquiterpene
• triterpene

Other

• Dodonaea petiolaris yields the diterpene ent-3β-acetoxy- 15,16-epoxylabda-8(17),13(16),14-trien-18-oic acid (C₂₂H₂₈O₆) or its enantiomer.
• Salvia divinorum yields Salvinorin A, a psychotropic drug