![Geranylgeranyl pyrophosphate](https://upload.wikimedia.org/wikipedia/commons/f/fb/Geranylgeranyl_pyrophosphate.png)
Diterpenes are a class of chemical compounds composed of four
isoprene units, often with the molecular formula C
20H
32. They are biosynthesized by plants, animals and fungi via the
HMG-CoA reductase pathway, with
geranylgeranyl pyrophosphate
Geranylgeranyl pyrophosphate is an intermediate in the biosynthesis of diterpenes and di terpenoids. It is also the precursor to carotenoids, gibberellins, tocopherols, and chlorophylls.
It is also a precursor to geranylgeranylated proteins, wh ...
being a primary intermediate. Diterpenes form the basis for biologically important
compounds such as
retinol
Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family found in food and used as a dietary supplement. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xeroph ...
,
retinal
Retinal (also known as retinaldehyde) is a polyene chromophore. Retinal, bound to proteins called opsins, is the chemical basis of visual phototransduction, the light-detection stage of visual perception (vision).
Some microorganisms use reti ...
, and
phytol
Phytol (florasol, phytosol) is an acyclic hydrogenated diterpene alcohol that can be used as a precursor for the manufacture of synthetic forms of vitamin E and vitamin K1. In ruminants, the gut fermentation of ingested plant materials libera ...
. They are known to be
antimicrobial
An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...
and
antiinflammatory
Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as ...
.
Structures
![Taxadiene](https://upload.wikimedia.org/wikipedia/commons/d/d7/Taxadiene.svg)
As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present.
Biosynthesis
Diterpenes are derived from the addition of one
IPP unit to
FPP to form
geranylgeranyl-pyrophosphate (GGPP). From GGPP, structural diversity is achieved mainly by two classes of enzymes; the diterpene synthases and
cytochromes P450. Several diterpenes are produced by plants and
cyanobacteria. GGPP is also the precursor for the synthesis of the
phytane
Phytane is the isoprenoid alkane formed when phytol, a constituent of chlorophyll, loses its hydroxyl group. When phytol loses one carbon atom, it yields pristane. Other sources of phytane and pristane have also been proposed than phytol.
Pris ...
by the action of the enzyme geranylgeranyl reductase. This compound is used for the biosynthesis of
tocopherol
Tocopherols (; TCP) are a class of organic chemical compounds (more precisely, various methylated phenols), many of which have vitamin E activity. Because the vitamin activity was first identified in 1936 from a dietary fertility factor in rat ...
s and the
phytyl
Phytane is the isoprenoid alkane formed when phytol, a constituent of chlorophyll, loses its hydroxyl group. When phytol loses one carbon atom, it yields pristane. Other sources of phytane and pristane have also been proposed than phytol.
Pris ...
functional group is used in the formation of
chlorophyll ''a'',
ubiquinone
Coenzyme Q, also known as ubiquinone and marketed as CoQ10, is a coenzyme family that is ubiquitous in animals and most bacteria (hence the name ubiquinone). In humans, the most common form is coenzyme Q10 or ubiquinone-10.
It is a 1,4-benzoq ...
s,
plastoquinone
Plastoquinone (PQ) is an isoprenoid quinone molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. The most common form of plastoquinone, known as PQ-A or PQ-9, is a 2,3-dimethyl-1,4-benzoquinone m ...
and
phylloquinone
Phytomenadione, also known as vitamin K1 or phylloquinone, is a vitamin found in food and used as a dietary supplement. It is on the World Health Organization's List of Essential Medicines.
As a supplement it is used to treat certain bleeding ...
.
Diterpenoids
Diterpenes are formally defined as being
hydrocarbons
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or e ...
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
Retinol, also called vitamin A1, is a fat-soluble vitamin in the vitamin A family found in food and used as a dietary supplement. As a supplement it is used to treat and prevent vitamin A deficiency, especially that which results in xeroph ...
and
phytol
Phytol (florasol, phytosol) is an acyclic hydrogenated diterpene alcohol that can be used as a precursor for the manufacture of synthetic forms of vitamin E and vitamin K1. In ruminants, the gut fermentation of ingested plant materials libera ...
.
Taxanes
Taxane
Taxanes are a class of diterpenes. They were originally identified from plants of the genus ''Taxus'' (yews), and feature a taxadiene core. Paclitaxel (Taxol) and docetaxel (Taxotere) are widely used as chemotherapy agents. Cabazitaxel was FDA ap ...
s are class of diterpenoids featuring a
taxadiene
Taxadiene (taxa-4,11-diene) is a diterpene. Taxadiene is the first committed intermediate in the synthesis of taxol. Six hydroxylation reactions, and a few others, are needed to convert taxadiene to baccatin III.
Enzymatically, taxadiene is prod ...
core. They are produced by plants of the genus ''
Taxus
''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. They are relatively slow-growing and can be very long-lived, and reach heights of , with trunk girth averaging . They have reddish bark, lanceolate, flat ...
'' (yew trees) and are widely used as
chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs ( chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothe ...
agents.
See also
*
Abeotaxane
*
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 func ...
*
Sesquiterpene
Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificat ...
*
Triterpene
Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squa ...
Other
* ''Dodonaea petiolaris'' yields the diterpene
''ent''-3β-acetoxy-15,16-epoxylabda-8(17),13(16),14-trien-18-oic acid (C
22H
28O
6) or its enantiomer.
* ''
Salvia divinorum'' yields
Salvinorin A
Salvinorin A is the main active psychotropic molecule in ''Salvia divinorum''. Salvinorin A is considered a dissociative hallucinogen.
It is structurally distinct from other naturally occurring hallucinogens (such as DMT, psilocybin, an ...
, a psychotropic drug
References
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