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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] |
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] |
Cucurbitane
Cucurbitane is a class of chemical compounds with formula ( CAS number 65441-59-0). It is a polycyclic hydrocarbon, specifically triterpene. It is also an isomer of lanostane (specifically 19(10→9β)-abeolanostane), from which it differs by the formal shift of a methyl group (carbon number 19) from the 10 to the 9β position in the standard steroid numbering scheme.Satish Kumar and Raj Kumar (1991), ''Dictionary of Biochemistry''. Anmol Publications, India 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-cucurbitane.svg, 5α-Cucurbitane File:5beta-cucurbitane.svg, 5β-Cucurbitane Derivatives Natural compounds Compounds with the basic cucurbitane skeleton are found in many plants, and some are important phytopharmaceuticals. Natural cucurbitane-related compounds include: Named * Balsaminapentaol, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lanosterol
Lanosterol is a tetracyclic triterpenoid and is the compound from which all animal and fungal steroids are derived. By contrast plant steroids are produced via cycloartenol. Role in biosynthesis of other steroids Elaboration of lanosterol under enzyme catalysis leads to the core structure of steroids. 14-Demethylation of lanosterol by CYP51 eventually yields cholesterol. Biosynthesis Research Lanosterol has been identified as a key component in maintaining eye lens clarity. Pre-clinical research has identified Lanosterol as a possible agent for the reversal and prevention of cataracts. In vivo experiments on dogs showed significant reversal of cataracts within 6 weeks of lanosterol injection. In 2018, Lanosterol was shown to improve lens clarity in cells with lens clouding due to aging or physical stressors. A subsequent study found positive results on the optics of the lens in mice with cataracts (Wang, Hoshino,Uesugi, Yagi, Pierscionek and Andley (2022). Use Lanosterol is a ... [...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] |
Chemical Compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element is therefore not a compound. A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken and/or new bonds formed. There are four major types of compounds, distinguished by how the constituent atoms are bonded together. Molecular compounds are held together by covalent bonds; ionic compounds are held together by ionic bonds; intermetallic compounds are held together by metallic bonds; coordination complexes are held together by coordinate covalent bonds. Non-stoichiometric compounds form a disputed marginal case. A chemical formula specifies the number of atoms of each element in a compound molecule, using the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycyclic Hydrocarbon
A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. PAHs are uncharged, non-polar and planar. Many are colorless. Many of them are found in coal and in oil deposits, and are also produced by the combustion of organic matter—for example, in engines and incinerators or when biomass burns in forest fires. Polycyclic aromatic hydrocarbons are discussed as possible starting materials for abiotic syntheses of materials required by the earliest forms of life. Nomenclature and structure The terms polyaromatic hydrocarbon or polynuclear aromatic hydrocarbon are also used for this concept. By definition, polycyclic aromatic hydrocarbons have multiple rings, precluding benzene from being considered a PAH. Some sources, such as the US EPA and CDC, consider naphthalene to be the simplest PAH. Other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereoisomer
In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space. This contrasts with structural isomers, which share the same molecular formula, but the bond connections or their order differs. By definition, molecules that are stereoisomers of each other represent the same structural isomer. Enantiomers Enantiomers, also known as optical isomers, are two stereoisomers that are related to each other by a reflection: they are mirror images of each other that are non-superposable. Human hands are a macroscopic analog of this. Every stereogenic center in one has the opposite configuration in the other. Two compounds that are enantiomers of each other have the same physical properties, except for the direction in which they rotate polarized light and how they interact with different optical isom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, Carbon-12, C and Carbon-13, C being stable, while Carbon-14, C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the Timeline of chemical element discoveries#Ancient discoveries, few elements known since antiquity. Carbon is the 15th Abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the Abundance of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxyl Group
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy groups. Both the negatively charged anion , called hydroxide, and the neutral radical , known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term ''hydroxyl'' refers to the hydroxyl radical () only, while the functional group is called a ''hydroxy group''. Properties Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be readily deprotonated due to a large difference between the electronegativity of oxygen (3.5) and that of hydrogen (2.1). Hydroxy-containing compounds engage in intermolecular hydrogen bonding increasing the electrostatic attraction between molecules and thus to higher boiling and melting points than found for compounds that lack this func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biogenesis
Spontaneous generation is a superseded scientific theory that held that living creatures could arise from nonliving matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas, could arise from inanimate matter such as dust, or that maggots could arise from dead flesh. The doctrine of spontaneous generation was coherently synthesized by Aristotle, who compiled and expanded the work of earlier natural philosophers and the various ancient explanations for the appearance of organisms. Spontaneous generation was taken as scientific fact for two millennia. Though challenged in the 17th and 18th centuries by the experiments of Francesco Redi and Lazzaro Spallanzani, it was not discredited until the work of the French chemist Louis Pasteur and the Irish physicist John Tyndall in the mid-19th century. Rejection of spontaneous generation is no longer controversial among biologists. By the middle of the 19th century, experiments by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Precursor
In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry, the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway, such as a protein precursor. Illicit drug precursors In 1988, the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances introduced detailed provisions and requirements relating the control of precursors used to produce drugs of abuse. In Europe the Regulation (EC) No. 273/2004 of the European Parliament and of the Council on drug precursors was adopted on 11 February 2004. (European law on drug precursors) Illicit explosives precursors On January 15, 2013, the Regulation (EU) No. 98/2013 of the European Parliament and of the Council on the marketing and use of explosives precursors was adopted. The Regulation harmonises rules across Europe on the making available, introduction, possession and us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
