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