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Sterol
A sterol is any organic compound with a Skeletal formula, skeleton closely related to Cholestanol, cholestan-3-ol. The simplest sterol is gonan-3-ol, which has a formula of , and is derived from that of gonane by replacement of a hydrogen atom on C3 position by a hydroxyl group. It is therefore an alcohol (chemistry), alcohol of gonane. More generally, any compounds that contain the gonane structure, additional functional groups, and/or modified ring systems derived from gonane are called steroids. Therefore, sterols are a subgroup of the steroids. They occur naturally in most Eukaryote, eukaryotes, including plants, animals, and fungi, and can also be produced by some bacteria (however likely with different functions). The most familiar type of animal sterol is cholesterol, which is vital to the structure of the cell membrane, and functions as a precursor to fat-soluble vitamins and steroid hormones. While technically alcohols, sterols are classified by biochemists as lipids (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesterol
Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all animal Cell (biology)#Eukaryotic cells, cells and is an essential structural and cholesterol signaling, signaling component of animal cell membranes. In vertebrates, hepatocyte, hepatic cells typically produce the greatest amounts. In the brain, astrocytes produce cholesterol and transport it to neurons. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as ''Mycoplasma'', which require cholesterol for growth. Cholesterol also serves as a Precursor (chemistry), precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Elevated levels of cholesterol in the blood, especially when bound to low-density lipoprotein (LDL, often referred to as "bad cholesterol"), may increase the risk of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytosterol
Phytosterols are phytosteroids, similar to cholesterol, that serve as structural components of biological membranes of plants. They encompass plant sterols and stanol ester, stanols. More than 250 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols. Phytosterol-enriched foods and dietary supplements have been marketed for decades. Despite well-documented LDL cholesterol-lowering effects from long-term consumption of phytosterols, there is insufficient evidence for an effect on cardiovascular diseases, fasting blood sugar, glycated hemoglobin, or overall mortality rate. Structure They have a fused polycyclic structure and vary in carbon side chains and / or presence or absence of a double bond (saturation). They are divided into 4,4-dimethyl phytosterols, 4-monomethyl phytosterols, and 4-desmethyl phytosterols based on the location of methyl groups at the carbon-4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroid
A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and as signal transduction, signaling molecules. Examples include the lipid cholesterol, sex hormones estradiol and testosterone, anabolic steroids, and the anti-inflammatory corticosteroid drug dexamethasone. Hundreds of steroids are found in Fungus, fungi, plants, and animals. All steroids are manufactured in cells from a sterols, sterol: Cholesterol, cholesterol (animals), lanosterol (opisthokonts), or cycloartenol (plants). All three of these molecules are produced via Cyclic compound, cyclization of the triterpene squalene. Structure The steroid nucleus (parent structure, core structure) is called gonane (cyclopentanoperhydrophenanthrene). It is typically composed of seventeen carbon atoms, bonded in fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campesterol
Campesterol is a phytosterol whose chemical structure is similar to that of cholesterol, and is one of the ingredients for E number E499. Natural occurrences Many vegetables, fruits, nuts, and seeds contain campesterol, but in low concentrations. Banana, pomegranate, pepper, coffee, grapefruit, cucumber, onion, oat, potato, and lemon grass (citronella) are few examples of common sources containing campesterol at roughly 1–7 mg/100 g of the edible portion. In contrast, canola and corn oils contain as much as 16–100 mg/100 g. Levels are variable and are influenced by geography and growing environment. In addition, different strains have different levels of plant sterols. A number of new genetic strains are currently being engineered with the goal of producing varieties high in campesterol and other plant sterols. It is also found in dandelion coffee. It is so named because it was first isolated from the rapeseed (''Brassica campestris''). Precursor o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterol
A sterol is any organic compound with a Skeletal formula, skeleton closely related to Cholestanol, cholestan-3-ol. The simplest sterol is gonan-3-ol, which has a formula of , and is derived from that of gonane by replacement of a hydrogen atom on C3 position by a hydroxyl group. It is therefore an alcohol (chemistry), alcohol of gonane. More generally, any compounds that contain the gonane structure, additional functional groups, and/or modified ring systems derived from gonane are called steroids. Therefore, sterols are a subgroup of the steroids. They occur naturally in most Eukaryote, eukaryotes, including plants, animals, and fungi, and can also be produced by some bacteria (however likely with different functions). The most familiar type of animal sterol is cholesterol, which is vital to the structure of the cell membrane, and functions as a precursor to fat-soluble vitamins and steroid hormones. While technically alcohols, sterols are classified by biochemists as lipids (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ergosterol
Ergosterol (ergosta-5,7,22-trien-3β-ol) is a mycosterol found in cell membranes of fungi and protozoa, serving many of the same functions that cholesterol serves in animal cells. Because many fungi and protozoa cannot survive without ergosterol, the enzymes that synthesize it have become important targets for drug discovery. In human nutrition, ergosterol is a provitamin form of vitamin D2; exposure to ultraviolet (UV) light causes a chemical reaction that produces vitamin D2. Role in fungi Ergosterol (ergosta-5,7,22-trien-3β-ol) is a sterol found in fungi, and named after ergot, the common name of members of the fungal genus '' Claviceps'' from which ergosterol was first isolated. Ergosterol is a component of yeast and other fungal cell membranes, serving many of the same functions that cholesterol serves in animal cells. Its specificity in higher fungi is thought to be related to the climatic instabilities (highly varying humidity and moisture conditions) encountered by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 number E499, and may be used in food manufacturing to increase the phytosterol content, potentially lowering the levels of LDL cholesterol. Discovery Once called ''Wulzen factor'' in the mid-20th century, stigmasterol was discovered by the University of California physiologist Rosalind Wulzen (born 1886). Natural occurrences Stigmasterol is an unsaturated phytosterol occurring in the plant fats or oils of numerous plants, such as soybean, calabar bean, and rape seed, and in herbs used in herbalism practices, including the Chinese herbs '' Ophiopogon japonicus'' (Mai men dong), in '' Mirabilis jalapa''. Stigmasterol is a constituent of various vegetables, legumes, nuts, seeds, and unpasteurized milk. Pasteurization will inactiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids are broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/ unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholestanol
5β-Coprostanol (5β-cholestan-3β-ol) is a 27-carbon stanol formed from the net reductive metabolism 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. 5β-coprostanol is thought to be exclusively bacterial in origin. Chemical properties Solubility 5β-coprostanol has a low water solubility, and consequently a high octanol-water partition coefficient . In other words, 5β-coprostanol has an affinity nearly 1 billion times higher for octanol than for water. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Membrane
The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space). The cell membrane consists of a lipid bilayer, made up of two layers of phospholipids with cholesterols (a lipid component) interspersed between them, maintaining appropriate membrane fluidity at various temperatures. The membrane also contains membrane proteins, including integral proteins that span the membrane and serve as membrane transporters, and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes to facilitate interaction with the cell's environment. Glycolipids embedded in the outer lipid layer serve a similar purpose. The cell membrane controls the movement of substances in and out of a cell, being selectively permeable to ions and organic mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholestenol
Cholestenol refers to any sterol compound that differs from cholestane by the addition of a double bond and an alcohol group. By the definition of sterols, the alcohol group appears at the C-3 position; the position of the double bond is not fixed. * Allocholesterol is Δ-4-Cholestenol. * Cholesterol is Δ5-cholestenol. ** Epicholesterol is an epimer, 3α-Cholesterol. * Lathosterol is Δ7-cholestenol. It has been found in the skins of rats. It can be converted to cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ... in mammals. * Zymostenol is Δ-8-Cholestenol. See also * C27H46O References {{reflist Cholestanes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
