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Ergostane
Ergostane is a tetracyclic triterpene, also known as 24''S''-methylcholestane. The compound itself has no known uses; however various functionalized analogues are produced by plants and animals. The most important of these are the heavily derivatised withanolides. However simpler forms do exist, such as the sterane campestane (24''R''-methylcholestane). Along with cholestane and stigmastane, this sterane is used as a biomarker for early eukaryotes. See also * Cholane * Cholestane * Lanostane Lanostane or 4,4,14α-trimethylcholestane is a chemical compound with formula . It is a polycyclic hydrocarbon, specifically a triterpene. It is an isomer of cucurbitane. The name is applied to two stereoisomers, distinguished by the prefixes 5Π... References {{Reflist Triterpenes Biomarkers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Withanolide
Withanolides are a group of at least 300 naturally occurring steroids built on an ergostane skeleton. They occur as secondary metabolites primarily in genera of the Nightshade family, for example in the tomatillo. Structurally, withanolides consist of a steroid backbone bound to a lactone or one of its derivatives; they are produced via oxidation of steroids. It remains unknown to what end withanolides are produced; they may act as a deterrent for feeding insect larvae and other herbivores. Genera within the nightshade family that produce withanolides include: ''Datura'', ''Iochroma'', ''Lycium'', ''Nicandra'', ''Physalis'', '' Salpichroa'', ''Solanum'', '' Mandragora'', ''Withania'', and '' Jaborosa''. No withanolide has been discovered in ''Nicotiana'' to date. Examples Withaferin A, the first withanolide to be isolated, was found in winter cherry (''Withania somnifera'') and Acnistus arborescens. Salpichrolides A, B and G (isolated from ''Salpichroa origanifolia'') exh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campestane
Campestane or 24''R''-methylcholestane is a tetracyclic triterpene. Its derivative campesterol (campest-5-en-3β-ol) was first isolated from the rapeseed (''Brassica campestris''), hence the name. See also * Cholestane * Ergostane Ergostane is a tetracyclic triterpene, also known as 24''S''-methylcholestane. The compound itself has no known uses; however various functionalized analogues are produced by plants and animals. The most important of these are the heavily derivati ... (24''S''-methylcholestane) * Campestanol (Campestan-3β-ol) References {{Reflist Triterpenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholane
Cholane is a triterpene which can exist as either of two stereoisomers, 5α-cholane and 5β-cholane. Its name is derived from el, χολή (chole) meaning 'bile' in reference to its original discovery from the bile of the American bullfrog (''Rana catesbeiana''). The compound itself has no known uses. However, various functionalized analogues are produced by plants and animals, typically in the form of sterols, steroids and bile acids (e.g. cholic acid). Image:5alpha-Cholane.svg, 5α-Cholane Image:5beta-Cholane.svg, 5β-Cholane See also * Cholestane * Ergostane Ergostane is a tetracyclic triterpene, also known as 24''S''-methylcholestane. The compound itself has no known uses; however various functionalized analogues are produced by plants and animals. The most important of these are the heavily derivati ... References External links * {{MeshName, Cholanes Triterpenes Cholanes Cyclopentanes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 squalene, the precursor to all steroids. Structures Triterpenes exist in a great variety of structures. Nearly 200 different skeletons have been identified. These skeletons may be broadly divided according to the number of rings present. In general pentacyclic structures (5 rings) tend to dominate. Squalene is biosynthesized through the head-to-head condensation of two farnesyl pyrophosphate units. This coupling converts a pair of C15 components into a C30 product. Squalene serves as precursor for the formation of many triterpenoids, including bacterial hopanoids and eukaryotic sterols. Triterpenoids By definition triterpenoids are triterpenes that possess heteroatoms, usually oxygen. The terms ''triterpene'' and ''triterpenoid'' oft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterane
Sterane (cyclopentanoperhydrophenanthrenes) compounds are a class of tetracyclic compounds derived from steroids or sterols via diagenetic and catagenetic degradation and saturation. Steranes have an androstane skeleton with a side chain at carbon C-17. The sterane structure constitutes the core of all sterols. Steranes are sometimes used as biomarkers for the presence of eukaryotic cells. Steranes may be rearranged to diasteranes during diagenesis (C-27 to C-30, rearrangement at C-18 and C-19, no R at C-24). Oils from clastic source rocks tend to be rich in diasteranes. Cholesterol and its derivatives (such as progesterone, aldosterone, cortisol, and testosterone), are common examples of compounds with the cyclopentanoperhydrophenanthrene nucleus. See also * Cholestane Cholestane is a saturated tetracyclic triterpene. This 27-carbon biomarker is produced by diagenesis of cholesterol and is one of the most abundant biomarkers in the rock record. Presence of cholestane, its d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholestane
Cholestane is a saturated tetracyclic triterpene. This 27-carbon biomarker is produced by diagenesis of cholesterol and is one of the most abundant biomarkers in the rock record. Presence of cholestane, its derivatives and related chemical compounds in environmental samples is commonly interpreted as an indicator of animal life and/or traces of O2, as animals are known for exclusively producing cholesterol, and thus has been used to draw evolutionary relationships between ancient organisms of unknown phylogenetic origin and modern metazoan taxa. Cholesterol is made in low abundance by other organisms (e.g., rhodophytes, land plants), but because these other organisms produce a variety of sterols it cannot be used as a conclusive indicator of any one taxon. It is often found in analysis of organic compounds in petroleum. Background Cholestane is a saturated C-27 animal biomarker often found in petroleum deposits. It is a diagenetic product of cholesterol, which is an organic molec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stigmastane
Stigmastane or 24''R''-ethylcholestane is a tetracyclic triterpene, along with cholestane and ergostane, this sterane is used as a biomarker for early eukaryotes. File:5α-Stigmastane.svg, 5α-Stigmastane File:5β-Stigmastane.svg, 5β-Stigmastane See also * Stigmastanol (Stigmastan-3β-ol) * β-Sitosterol (Stigmast-5-en-3β-ol) * Stigmasterol Stigmasterol – a plant sterol (''phytosterol'') – is among the most abundant of plant sterols, having a major function to maintain the structure and physiology of cell membranes. In the European Union, it is a food additive listed with E numb ... (Stigmast-5,22-dien-3β-ol) References {{Reflist Triterpenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. as cited in Biomarkers are used in many scientific fields. Medicine Biomarkers used in the medical field, are a part of a relatively new clinical toolset categorized by their clinical applications. The three main classes are molecular biomarkers, cellular biomarkers or imaging biomarkers. All three types of biomarkers have a clinical role in narrowing or guiding treatment decisions and follow a sub-categorization of being either predictive, prognostic, or diagnostic. Predictive Predictive molecular, cellular, or imaging biomarkers that pass validation can serve as a method of predicting clinical outcomes. Predictive biomarkers are used to help optimize id ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholestane
Cholestane is a saturated tetracyclic triterpene. This 27-carbon biomarker is produced by diagenesis of cholesterol and is one of the most abundant biomarkers in the rock record. Presence of cholestane, its derivatives and related chemical compounds in environmental samples is commonly interpreted as an indicator of animal life and/or traces of O2, as animals are known for exclusively producing cholesterol, and thus has been used to draw evolutionary relationships between ancient organisms of unknown phylogenetic origin and modern metazoan taxa. Cholesterol is made in low abundance by other organisms (e.g., rhodophytes, land plants), but because these other organisms produce a variety of sterols it cannot be used as a conclusive indicator of any one taxon. It is often found in analysis of organic compounds in petroleum. Background Cholestane is a saturated C-27 animal biomarker often found in petroleum deposits. It is a diagenetic product of cholesterol, which is an organic molec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lanostane
Lanostane or 4,4,14α-trimethylcholestane is a chemical compound with formula . It is a polycyclic hydrocarbon, specifically a triterpene. It is an isomer of cucurbitane. The name is applied to two stereoisomers, distinguished by the prefixes 5α- and 5β-, which differ by the handedness of the bonds at a particular carbon atom (number 5 in the standard steroid numbering scheme). File:5alpha-lanostane.svg, 5α-Lanostane File:5beta-lanostane.svg, 5β-Lanostane Replacement of a hydrogen atom attached to carbon number 3 in the 5α isomer with a hydroxyl group results in lanosterol, the biogenetic precursor of the steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...s in animals. References {{Saponins Lanostanes Triterpenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triterpenes
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 squalene, the precursor to all steroids. Structures Triterpenes exist in a great variety of structures. Nearly 200 different skeletons have been identified. These skeletons may be broadly divided according to the number of rings present. In general pentacyclic structures (5 rings) tend to dominate. Squalene is biosynthesized through the head-to-head condensation of two farnesyl pyrophosphate units. This coupling converts a pair of C15 components into a C30 product. Squalene serves as precursor for the formation of many triterpenoids, including bacterial hopanoids and eukaryotic sterols. Triterpenoids By definition triterpenoids are triterpenes that possess heteroatoms, usually oxygen. The terms ''triterpene'' and ''triterpenoid'' oft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
