The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes", terpenoids contain additional functional groups, usually containing oxygen. When combined with the hydrocarbon terpenes, terpenoids comprise about 80,000 compounds. They are the largest class of plant secondary metabolites, representing about 60% of known natural products. Many terpenoids have substantial pharmacological bioactivity and are therefore of interest to medicinal chemists.
Terpenes are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. Terpenes are further classified by the number of carbons: monoterpenes (C10), sesquiterpenes (C15), diterpenes (C20), as examples. The terpene alpha-pinene, is a major component of the common solvent, turpentine.
Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil, palmarosa oil. It is a colorless oil, although commercial samples can appear yellow. It has low solubility in water, but it is soluble in common organic solvents. The functional group derived from geraniol is called geranyl.
Sabinene is a natural bicyclic monoterpene with the molecular formula C10H16. It is isolated from the essential oils of a variety of plants including Marjoram, holm oak (Quercus ilex) and Norway spruce (Picea abies). It has a strained ring system with a cyclopentane ring fused to a cyclopropane ring.
Farnesyl pyrophosphate (FPP), also known as farnesyl diphosphate (FDP), is an intermediate in the biosynthesis of terpenes and terpenoids such as sterols and carotenoids. It is also used in the synthesis of CoQ, as well as dehydrodolichol diphosphate.
Geranylgeranyl pyrophosphate is an intermediate in the biosynthesis of diterpenes and diterpenoids. It is also the precursor to carotenoids, gibberellins, tocopherols, and chlorophylls.
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 modifications such as oxidation or rearrangement produce the related sesquiterpenoids.
The enzyme (+)-δ-cadinene synthase catalyzes the chemical reaction
In enzymology, bornyl diphosphate synthase (BPPS) (EC 5.5.1.8) is an enzyme that catalyzes the chemical reaction
The enzyme aristolochene synthase catalyzes the chemical reaction
The enzyme pentalenene synthase catalyzes the chemical reaction
In enzymology, a farnesyltranstransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a geranyltranstransferase is an enzyme that catalyzes the chemical reaction
Aucubin is an iridoid glycoside. Iridoids are commonly found in plants and function as defensive compounds. Iridoids decrease the growth rates of many generalist herbivores.
Juvabione, historically known as the paper factor, is the methyl ester of todomatuic acid. Both are sesquiterpenes (C15) found in the wood of true firs of the genus Abies. They occur naturally as part of a mixture of sesquiterpenes based upon the bisabolane scaffold. Sesquiterpenes of this family are known as insect juvenile hormone analogues (IJHA) because of their ability to mimic juvenile activity in order to stifle insect reproduction and growth. These compounds play important roles in conifers as the second line of defense against insect induced trauma and fungal pathogens.
Secologanin is a secoiridoid monoterpene synthesized from geranyl pyrophosphate in the mevalonate pathway. Secologanin then proceeds with dopamine or tryptamine to form ipecac and terpene indole alkaloids, respectively.
Geranyl diphosphate 2-C-methyltransferase is an enzyme with systematic name S-adenosyl-L-methionine:geranyl-diphosphate 2-C-methyltransferase. This enzyme catalyses the following chemical reaction
All-trans-nonaprenyl-diphosphate synthase is an enzyme with systematic name geranyl-diphosphate:isopentenyl-diphosphate transtransferase . This enzyme catalyses the following chemical reaction
Sclareol cyclase (EC 3.1.7.4, geranylgeranyl pyrophosphate:sclareol cyclase, geranylgeranyl pyrophosphate-sclareol cyclase, GGPP:sclareol cyclase) is an enzyme with systematic name geranylgeranyl-diphosphate diphosphohydrolase (sclareol-forming). This enzyme catalyses the following chemical reaction
Valencene synthase is an enzyme with systematic name (2E,6E)-farnesyl-diphosphate diphosphate-lyase (valencene-forming). It is a terpene cyclase enzyme responsible for the biosynthesis of valencene, a sesquiterpene, using farnesyl pyrophosphate as its substrate. The first such enzyme was isolated using orange cDNA. This enzyme catalyses the following chemical reaction
