Terpenes are a class of natural products consisting of compounds with the formula (C5H8)n for n ≥ 2. Terpenes are major biosynthetic building blocks. Comprising more than 30,000 compounds, these unsaturated hydrocarbons are produced predominantly by plants, particularly conifers. In plants, terpenes and terpenoids are important mediators of ecological interactions, while some insects use some terpenes as a form of defense. Other functions of terpenoids include cell growth modulation and plant elongation, light harvesting and photoprotection, and membrane permeability and fluidity control.
Nepetalactone is a name for multiple iridoid analog stereoisomers. Nepetalactones are produced by Nepeta cataria (catnip) and many other plants belonging to the genus Nepeta, in which they protect these plants from herbivorous insects by functioning as insect repellents. They are also produced by many aphids, in which they are sex pheromones. Nepetalactones are cat attractants, and cause the behavioral effects that catnip induces in domestic cats. However, they affect visibly only about two thirds of adult cats. They produce similar behavioral effects in many other felids, especially in lions and jaguars. In 1941, the research group of Samuel M. McElvain was the first to determine the structures of nepetalactones and several related compounds.
Geraniol is a monoterpenoid and an alcohol. It is the primary component of citronella oil and is a primary component of rose oil and 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.
Citral is an acyclic monoterpene aldehyde. Being a monoterpene, it is made of two isoprene units. Citral is a collective term which covers two geometric isomers that have their own separate names; the E-isomer is named geranial or citral A. The Z-isomer is named neral or citral B. These stereoisomers occur as a mixture, often not in equal proportions; e.g. in essential oil of Australian ginger, the neral to geranial ratio is 0.61.
Geranyl pyrophosphate (GPP), also known as geranyl diphosphate (GDP), is the pyrophosphate ester of the terpenoid geraniol. Its salts are colorless. It is a precursor to many natural products.
Grandisol is a natural organic compound with the molecular formula C10H18O. It is a monoterpene containing a cyclobutane ring, an alcohol group, an alkene group and two chiral centers (one of which is quaternary).
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 functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries.
Flavones are a class of flavonoids based on the backbone of 2-phenylchromen-4-one (2-phenyl-1-benzopyran-4-one).
Camptothecin (CPT) is a topoisomerase inhibitor. It was discovered in 1966 by M. E. Wall and M. C. Wani in systematic screening of natural products for anticancer drugs. It was isolated from the bark and stem of Camptotheca acuminata, a tree native to China used in traditional Chinese medicine. It has been used clinically in China for the treatment of gastrointestinal tumors. CPT showed anticancer activity in preliminary clinical trials, especially against breast, ovarian, colon, lung, and stomach cancers. However, it has low solubility and adverse effects have been reported when used therapeutically, so synthetic and medicinal chemists have developed numerous syntheses of camptothecin and various derivatives to increase the benefits of the chemical, with good results. Four CPT analogues have been approved and are used in cancer chemotherapy today: topotecan, irinotecan, belotecan, and trastuzumab deruxtecan. Camptothecin has also been found in other plants including Chonemorpha fragrans.
In molecular biology, this protein domain belongs to the terpene synthase family (TPS). Its role is to synthesize terpenes, which are part of primary metabolism, such as sterols and carotene, and also part of the secondary metabolism. This entry will focus on the N terminal domain of the TPS protein.
8-hydroxygeraniol dehydrogenase (EC 1.1.1.324, 8-hydroxygeraniol oxidoreductase, CYP76B10, G10H, CrG10H, SmG10H, acyclic monoterpene primary alcohol:NADP+ oxidoreductase) is an enzyme with systematic name (6E)-8-hydroxygeraniol:NADP+ oxidoreductase. This enzyme catalyses the following chemical reaction
Geranial dehydrogenase (EC 1.2.1.86, GaDH, geoB (gene)) is an enzyme with systematic name geranial:NAD+ oxidoreductase. This enzyme catalyses the following chemical reaction
Tetrahydrocannabinolic acid (THCA) synthase is an enzyme responsible for catalyzing the formation of THCA from cannabigerolic acid (CBGA). THCA is the direct precursor of tetrahydrocannabinol (THC), the principal psychoactive component of cannabis, which is produced from various strains of Cannabis sativa. Therefore, THCA synthase is considered to be a key enzyme controlling cannabis psychoactivity. Polymorphisms of THCA synthase result in varying levels of THC in Cannabis plants, resulting in "drug-type" and "fiber-type" C. sativa varieties.
Linalool dehydratase (EC 4.2.1.127, linalool hydro-lyase (myrcene-forming)) is an enzyme with systematic name (3S)-linalool hydro-lyase (myrcene-forming). This enzyme catalyses the following chemical reaction
(−)-α-Pinene synthase is an enzyme with systematic name geranyl-diphosphate diphosphate-lyase [cyclizing, (−)-α-pinene-forming]. This enzyme catalyses the following chemical reaction
Geraniol isomerase is an enzyme with systematic name geraniol hydroxymutase. This enzyme catalyses the following chemical reaction
Akuammicine is a monoterpene indole alkaloid of the Vinca sub-group. It is found in the Apocynaceae family of plants including Picralima nitida, Vinca minor and the Aspidosperma.
8-Oxogeranial is a chemical substance, that is a monoterpene. The terpenoid is produced by 8-hydroxygeraniol dehydrogenase which uses 8-hydroxygeraniol as its substrate. 8-Oxogeranial is itself a substrate for iridoid synthase which synthesizes cis–trans-iridodial and cis–trans-nepetalactol.
Harpagoside is a natural product found in the plant Harpagophytum procumbens, also known as devil's claw. It is the active chemical constituent responsible for the medicinal properties of the plant, which have been used for centuries by the Khoisan people of southern Africa to treat diverse health disorders, including fever, diabetes, hypertension, and various blood related diseases.
Cytochrome P450, family 76, also known as CYP76, is a cytochrome P450 family in land plants, related to the biosynthesis of many plant monoterpenes and diterpenes such as 8-hydroxygeraniol, tanshinone and alkannin. The first gene identified in this family is the CYP76A1 and CYP76A2 from the eggplant.
