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Coprostane
Coprostane, also known as 5β-cholestane, is a steroid and a parent compound of a variety of steroid derivatives, such as ecdysone and coprostanol 5β-Coprostanol (5β-cholestan-3β-ol) is a 27-carbon stanol formed from the biohydrogenation of cholesterol (cholest-5en-3β-ol) in the gut of most higher animals and birds. This compound has frequently been used as a biomarker for the presen .... References Cholestanes {{steroid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coprostanol
5β-Coprostanol (5β-cholestan-3β-ol) is a 27-carbon stanol formed from the biohydrogenation of cholesterol (cholest-5en-3β-ol) in the gut of most higher animals and birds. This compound has frequently been used as a biomarker for the presence of human faecal matter in the environment. Chemical properties Solubility 5β-coprostanol has a low water solubility, and consequently a high octanol-water partition coefficient (log Kow = 8.82). This means that in most environmental systems, 5β-coprostanol will be associated with the solid phase. Degradation In anaerobic sediments and soils, 5β-coprostanol is stable for many hundreds of years enabling it to be used as an indicator of past faecal discharges. As such, records of 5β-coprostanol from paleo-environmental archives have been used to further constrain the timing of human settlements in a region, as well as reconstruct relative changes in human populations and agricultural activities over several thousand years. Chemica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 as signaling molecules. Hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol (opisthokonts) or cycloartenol (plants). Lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene. The steroid core structure is typically composed of seventeen carbon atoms, bonded in four " fused" rings: three six-member cyclohexane rings (rings A, B and C in the first illustration) and one five-member cyclopentane ring (the D ring). Steroids vary by the functional groups attached to this four-ring core and by the oxidation state of the rings. Sterols are forms of steroids with a hydroxy group at position three and a skeleton derived from cholestane. ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parent Compound
In chemistry, a parent structure is the structure of an unadorned ion or molecule from which derivatives can be visualized. Parent structures underpin systematic nomenclature and facilitate classification. Fundamental parent structures have one or no functional groups and often have various types of symmetry. Benzene () is a chemical itself consisting of a hexagonal ring of carbon atoms with a hydrogen atom attached to each, and is the parent of many derivatives that have substituent atoms or groups replacing one or more of the hydrogens. Some parents are rare or nonexistent themselves, as in the case of porphine, though many simple and complex derivatives are known. File:Benzene circle.png, Benzene is the parent. File:Toluene-vec.svg, Toluene is a derivative of benzene. File:Porphyrin.svg, Porphine is the parent of porphyrins. File:PPIXtransH.png, Protoporphyrin IX is a natural derivative of the parent porphine. File:H2octaethylporphyrin.png , Octaethylporphyrin is a syntheti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Derivative
In chemistry, a derivative is a compound that is derived from a similar compound by a chemical reaction. In the past, derivative also meant a compound that ''can be imagined to'' arise from another compound, if one atom or group of atoms is replaced with another atom or group of atoms, but modern chemical language now uses the term structural analog for this meaning, thus eliminating ambiguity. The term "structural analogue" is common in organic chemistry. In biochemistry, the word is used for compounds that at least theoretically can be formed from the precursor compound. Chemical derivatives may be used to facilitate analysis. For example, melting point (MP) analysis can assist in identification of many organic compounds. A crystalline derivative may be prepared, such as a semicarbazone or 2,4-dinitrophenylhydrazone (derived from aldehydes or ketones), as a simple way of verifying the identity of the original compound, assuming that a table of derivative MP values is available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecdysone
Ecdysone is a prohormone of the major insect molting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. It is of steroidal structure. Insect molting hormones (ecdysone and its homologues) are generally called ecdysteroids. Ecdysteroids act as moulting hormones of arthropods but also occur in other related phyla where they can play different roles. In ''Drosophila melanogaster'', an increase in ecdysone concentration induces the expression of genes coding for proteins that the larva requires, and it causes chromosome puffs (sites of high expression) to form in polytene chromosomes. Recent findings in the laboratory of Chris Q. Doe have found a novel role of this hormone in regulating temporal gene transitions within neural stem cells of the fruit fly. Ecdysone and other ecdysteroids also appear in many plants mostly as a protection agent ( toxins or antifeedants) against herbivorous insects. These phytoecdysteroids have been reputed to have medicinal va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
