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Ginkgolide
Ginkgolides are biologically active terpenic lactones present in ''Ginkgo biloba''. They are diterpenoids with 20-carbon skeletons, which are biosynthesized from geranylgeranyl pyrophosphate. Examples Ginkgolide B Ginkgolide B, specifically, is a diterpenoid trilactone with six five-membered rings. It contains a spiro ,4nonane carbocyclic ring, a tetrahydrofuran ring, and a very specific tert-butyl group at one of the rings (Figure 1). The class of ginkgolides was first isolated from the tree ''Ginkgo biloba'' in 1932. Structural elucidation was accomplished in 1967 by Maruyama ''et al''. Background It is extracted from the root bark and leaves of the ''Ginkgo biloba'' (' meaning "silver apricot") tree found native in China. It is marketed to other countries that include Korea, France, the United States, etc. for the drug and clinical properties of the extracts. Present in the tree is less than 0.1 to 0.25% of ginkgolide B, the most abundant being ginkgolide A. Potential a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ginkgolides Structure
Ginkgolides are biologically active terpenic lactones present in ''Ginkgo biloba''. They are diterpenoids with 20-carbon skeletons, which are biosynthesized from geranylgeranyl pyrophosphate. Examples Ginkgolide B Ginkgolide B, specifically, is a diterpenoid trilactone with six five-membered rings. It contains a spiro ,4nonane carbocyclic ring, a tetrahydrofuran ring, and a very specific tert-butyl group at one of the rings (Figure 1). The class of ginkgolides was first isolated from the tree ''Ginkgo biloba'' in 1932. Structural elucidation was accomplished in 1967 by Maruyama ''et al''. Background It is extracted from the root bark and leaves of the ''Ginkgo biloba'' (' meaning "silver apricot") tree found native in China. It is marketed to other countries that include Korea, France, the United States, etc. for the drug and clinical properties of the extracts. Present in the tree is less than 0.1 to 0.25% of ginkgolide B, the most abundant being ginkgolide A. Potential a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bilobalide
Bilobalide is a biologically active terpenic trilactone present in ''Ginkgo biloba''. Chemistry Bilobalide is a main constituent of the terpenoids found in Ginkgo leaves. It also exists in minor amounts in the roots. It is a sesquiterpenoid, i.e. it has a 15-carbon skeleton. Its exact synthesis pathway from farnesyl pyrophosphate is still unknown. Biosynthesis Bilobalide and ginkgolide have similar biosynthetic pathways. Bilobalide is formed by partially degraded ginkgolide. Bilobalide is derived from geranylgeranyl pyrophosphate (GGPP), which is formed by addition of farnesyl pyrophosphate (FPP) to an isopentenyl pyrophosphate (IPP) unit to form a C15 sesquiterpene. Such formation went through the mevalonate pathway (MVA) and methylerythritol phosphate MEP pathway. In order to generate bilobalide, C20 ginkgolide 13 must form first. To transform from GGPP to abietenyl cation 5, a single bifunctional enzyme abietadiene synthase E1 is required. However, due to the complexity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levopimaradiene Synthase
Levopimaradiene synthase (EC 4.2.3.32, ''PtTPS-LAS'', ''LPS'', copalyl-diphosphate diphosphate-lyase bieta-8(14),12-diene-forming'') is an enzyme with systematic name (+)-copalyl-diphosphate diphosphate-lyase (abieta-8(14),12-diene-forming). This enzyme catalyses the following chemical reaction : (+)-copalyl diphosphate \rightleftharpoons abieta-8(14),12-diene + diphosphate In Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus within ..., the enzyme catalyses the initial cyclization step in the biosynthesis of ginkgolides. References External links * {{Portal bar, Biology, border=no EC 4.2.3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terpenoid
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. Plant terpenoids are used for their aromatic qualities and play a role in traditional herbal remedies. Terpenoids contribute to the scent of eucalyptus, the flavors of cinnamon, cloves, and ginger, the yellow color in sunflowers, and the red color in tomatoes. Well-known terpenoids include citral, menthol, camphor, salvinorin A in the plant '' Salvia di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ginkgo Biloba
''Ginkgo biloba'', commonly known as ginkgo or gingko ( ), also known as the maidenhair tree, is a species of tree native to China. It is the last living species in the order Ginkgoales, which first appeared over 290 million years ago. Fossils very similar to the living species, belonging to the genus ''Ginkgo'', extend back to the Middle Jurassic approximately 170 million years ago. The tree was cultivated early in human history and remains commonly planted. Ginkgo leaf extract is commonly used as a dietary supplement, but there is no scientific evidence that it supports human health or is effective against any disease. Etymology The genus name is regarded as a misspelling of the Japanese pronunciation ''gin kyo'' for the kanji 銀杏 meaning "silver apricot", which is found in Chinese herbology literature such as (Daily Use Materia Medica) (1329) and ''Compendium of Materia Medica'' published in 1578.T. Hori, A historical survey of Ginkgo biloba based on Japanese and Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MEP Pathway
The non-mevalonate pathway—also appearing as the mevalonate-independent pathway and the 2-''C''-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate (MEP/DOXP) pathway—is an alternative metabolic pathway for the biosynthesis of the isoprenoid precursors isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). The currently preferred name for this pathway is the MEP pathway, since MEP is the first committed metabolite on the route to IPP. Isoprenoid precursor biosynthesis The classical mevalonate pathway (MVA pathway or HMG-CoA reductase pathway) is a metabolic pathway for the biosynthesis of isoprenoid precursors: IPP and DMAPP. The MVA pathway is present in most eukaryotes and some bacteria. IPP and DMAPP serve as the basis for the biosynthesis of isoprenoid (terpenoid) molecules used in processes as diverse as protein prenylation, cell membrane maintenance, the synthesis of hormones, protein anchoring and ''N''-glycosylation in all three domains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycine Receptor Antagonists
Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid (carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinogenic amino acids. It is encoded by all the codons starting with GG (GGU, GGC, GGA, GGG). Glycine is integral to the formation of alpha-helices in secondary protein structure due to its compact form. For the same reason, it is the most abundant amino acid in collagen triple-helices. Glycine is also an inhibitory neurotransmitter – interference with its release within the spinal cord (such as during a ''Clostridium tetani'' infection) can cause spastic paralysis due to uninhibited muscle contraction. It is the only achiral proteinogenic amino acid. It can fit into hydrophilic or hydrophobic environments, due to its minimal side chain of only one hydrogen atom. History and etymology Glycine was discovered in 1820 by the French chemist Henri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpenes
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. 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. Structures 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 by the action of the enzyme geranylger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geranylgeranyl Diphosphate
Geranylgeranyl pyrophosphate is an intermediate in the biosynthesis of diterpenes and diterpenoids. It is also the precursor to carotenoids, gibberellins, tocopherols, and chlorophylls. It is also a precursor to geranylgeranylated proteins, which is its primary use in human cells. It is formed from farnesyl pyrophosphate by the addition of an isoprene unit from isopentenyl pyrophosphate. In ''Drosophila'', geranylgeranyl pyrophosphate is synthesised by HMG-CoA encoded by the Columbus gene. Geranylgeranyl pyrophosphate is utilised as a chemoattractant for migrating germ cells that have traversed the midgut epithelia. The attractant signal is produced at the gonadal precursors, directing the germ cells to these sites, where they will differentiate into eggs and spermatozoa (sperm). Related compounds * Farnesyl pyrophosphate * Geranylgeraniol * Geranyl pyrophosphate Geranyl pyrophosphate (GPP), also known as geranyl diphosphate (GDP), is the pyrophosphate ester of the terpenoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethylallyl Diphosphate
Dimethylallyl pyrophosphate (DMAPP; or alternatively, dimethylallyl diphosphate (DMADP); also isoprenyl pyrophosphate) is an isoprenoid precursor. It is a product of both the mevalonate pathway and the MEP pathway of isoprenoid precursor biosynthesis. It is an isomer of isopentenyl pyrophosphate (IPP) and exists in virtually all life forms. The enzyme isopentenyl pyrophosphate isomerase catalyzes isomerization between DMAPP and IPP. In the mevalonate pathway DMAPP is synthesised from mevalonic acid. In contrast, DMAPP is synthesised from HMBPP in the MEP pathway. At present, it is believed that there is crossover between the two pathways in organisms that use both pathways to create terpenes and terpenoid 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" ...s, such as in plants, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
