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Taxifolin
Taxifolin (5,7,3',4'-flavan-on-ol), also known as dihydroquercetin, belongs to the subclass flavanonols in the flavonoids, which in turn is a class of polyphenols. It is extracted from plants such as Siberian larch and milk thistle. Stereocenters Taxifolin has two stereocenters on the C-ring, as opposed to quercetin which has none. For example, (+)-taxifolin has (2''R'',3''R'')-configuration, making it one out of four stereoisomers that comprise two pairs of enantiomers. Natural occurrences Taxifolin is found in non-glutinous rice boiled with adzuki bean (adzuki-meshi). It can be found in conifers like the Siberian larch, ''Larix sibirica'', in Russia, in ''Pinus roxburghii'', in ''Cedrus deodara'' and in the Chinese yew, '' Taxus chinensis var. mairei''. It is also found in the silymarin extract from the milk thistle seeds. Taxifolin is present in vinegars aged in cherry wood. Taxifolin, and flavonoids in general, can be found in many beverages and products. Specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Flavanonol
The flavanonols (with two "o"s a.k.a. 3-hydroxyflavanone or 2,3-dihydroflavonol) are a class of flavonoids that use the 3-hydroxy-2,3-dihydro-2-phenylchromen-4-one (IUPAC name) backbone. Some examples include: * Taxifolin (or Dihydroquercetin) * Aromadedrin (or Dihydrokaempferol) * Engeletin (or Dihydrokaempferol-3-rhamnoside) Metabolism * Flavanone 3-dioxygenase * Flavonol synthase * Dihydroflavonol 4-reductase Glycosides Glycosides ( chrysandroside A and chrysandroside B) can be found in the roots of ''Gordonia chrysandra''. Xeractinol, a dihydroflavonol C-glucoside, can be isolated from the leaves of ''Paepalanthus argenteus var. argenteus''. Dihydro-flavonol glycosides (astilbin, neoastilbin, isoastilbin, neoisoastilbin, (2''R'', 3''R'')-taxifolin-3'-''O''-β-D-pyranoglucoside) have been identified in the rhizome of ''Smilax glabra ''Smilax glabra'', sarsaparilla, is a plant species in the genus ''Smilax''. It is native to flora of China, China, the Himalayas, and Indo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Flavonoid
Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids have the general structure of a 15-carbon skeleton, which consists of two phenyl rings (A and B) and a Heterocyclic compound, heterocyclic ring (C, the ring containing the embedded oxygen). This carbon structure can be abbreviated C6-C3-C6. According to the IUPAC nomenclature, they can be classified into: *flavonoids or bioflavonoids *isoflavonoids, derived from 3-phenylchromone, chromen-4-one (3-phenyl-1,4-benzopyran, benzopyrone) structure *neoflavonoids, derived from 4-phenylcoumarin (4-phenyl-1,2-benzopyran, benzopyrone) structure The three flavonoid classes above are all ketone-containing compounds and as such, anthoxanthins (flavones and flavonols). This class was the first to be termed bioflavonoids. The terms flavonoid and bioflavo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Arbutin
β-Arbutin, also known by its International Nomenclature of Cosmetic Ingredients (INCI) name, arbutin, is a glycosylated derivative of hydroquinone. β-Arbutin is naturally present in the leaves and bark of a variety of plants, notably the bearberry plant, ''Arctostaphylos uva-ursi''. Utilized as a biosynthetic active ingredient in topical treatments for skin lightening, β-arbutin is aimed at addressing hyperpigmentation issues. Its mechanism of action involves inhibiting the activity of tyrosinase, an essential enzyme for melanin synthesis in the human skin, thereby leading to a reduction in hyperpigmentation. It is important to distinguish β-arbutin from its structurally similar stereoisomer, α-arbutin, which exhibits similar effects in clinical applications. Properties Arbutin is a compound where a glucose molecule, specifically -glucose, is chemically bound to hydroquinone. In aqueous solutions, glucose can exist in one of three stereoisomeric forms: α, β, or γ, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Quercetin
Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor and is used as an ingredient in dietary supplements, beverages, and foods. Occurrence Quercetin is a flavonoid widely distributed in nature. The name has been used since 1857, and is derived from ''quercetum'' (oak forest), after the oak genus ''Quercus''. It is a naturally occurring polar auxin transport inhibitor. Quercetin is one of the most abundant dietary flavonoids, with an average daily consumption of 25–50 mg. In red onions, higher concentrations of quercetin occur in the outermost rings and in the part closest to the root, the latter being the part of the plant with the highest concentration. One study found that organically grown tomatoes had 79% more quercetin than non-organically grown fruit. Quercetin is present in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Stereoisomerism
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 enantiomers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Correlation
In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics it usually refers to the degree to which a pair of variables are '' linearly'' related. Familiar examples of dependent phenomena include the correlation between the height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the demand curve. Correlations are useful because they can indicate a predictive relationship that can be exploited in practice. For example, an electrical utility may produce less power on a mild day based on the correlation between electricity demand and weather. In this example, there is a causal relationship, because extreme weather causes people to use more electricity for heating or cooling. However, in g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Receptor Antagonist
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of receptor proteins.Pharmacology Guide: In vitro pharmacology: concentration-response curves ." '' GlaxoWellcome.'' Retrieved on December 6, 2007. They are sometimes called blockers; examples include alpha blockers, beta b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Methicillin-resistant Staphylococcus Aureus
Methicillin-resistant ''Staphylococcus aureus'' (MRSA) is a group of gram-positive bacteria that are genetically distinct from other strains of ''Staphylococcus aureus''. MRSA is responsible for several difficult-to-treat infections in humans. It caused more than 100,000 deaths worldwide attributable to antimicrobial resistance in 2019. MRSA is any strain of ''S. aureus'' that has developed (through mutation) or acquired (through horizontal gene transfer) a multiple drug resistance to beta-lactam antibiotics. Beta-lactam (β-lactam) antibiotics are a broad-spectrum group that include some penams (penicillin derivatives such as methicillin and oxacillin) and cephems such as the cephalosporins. Strains unable to resist these antibiotics are classified as methicillin-susceptible ''S. aureus'', or MSSA. MRSA infection is common in hospitals, prisons, and nursing homes, where people with open wounds, invasive devices such as catheters, and weakened immune systems are at greate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
In Vitro
''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and its subdisciplines are traditionally done in labware such as test tubes, flasks, Petri dishes, and microtiter plates. Studies conducted using components of an organism that have been isolated from their usual biological surroundings permit a more detailed or more convenient analysis than can be done with whole organisms; however, results obtained from ''in vitro'' experiments may not fully or accurately predict the effects on a whole organism. In contrast to ''in vitro'' experiments, ''in vivo'' studies are those conducted in living organisms, including humans, known as clinical trials, and whole plants. Definition ''In vitro'' (Latin language, Latin for "in glass"; often not italicized in English usage) studies are conducted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Ceftazidime
Ceftazidime, sold under the brand name Fortaz among others, is a third-generation cephalosporin antibiotic useful for the treatment of a number of bacterial infections. Specifically it is used for joint infections, meningitis, pneumonia, sepsis, urinary tract infections, malignant otitis externa, ''Pseudomonas aeruginosa'' infection, and vibrio infection. It is given by injection into a vein, muscle, or eye. Common side effects include nausea, allergic reactions, and pain at the site of injection. Other side effects may include ''Clostridioides difficile'' diarrhea. It is not recommended in people who have had previous anaphylaxis to a penicillin. Its use is relatively safe during pregnancy and breastfeeding. It is in the third-generation cephalosporin family of medications and works by interfering with the bacteria's cell wall. Ceftazidime was patented in 1978 and came into commercial use in 1984. It is on the World Health Organization's List of Essential Medicines. Ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Levofloxacin
Levofloxacin, sold under the brand name Levaquin among others, is a broad-spectrum antibiotic of the fluoroquinolone drug class. It is the left-handed isomer of the medication ofloxacin. It is used to treat a number of bacterial infections including acute bacterial sinusitis, pneumonia, '' H. pylori'' (in combination with other medications), urinary tract infections, Legionnaires' disease, chronic bacterial prostatitis, and some types of gastroenteritis. Along with other antibiotics it may be used to treat tuberculosis, meningitis, or pelvic inflammatory disease. It is available by mouth, intravenously, and in eye drop form. Common side effects include nausea, diarrhea, and trouble sleeping. A warning concerning all fluoroquinolones was issued in 2016: "An FDA safety review has shown that fluoroquinolones when used systemically (i.e. tablets, capsules, and injectable) are associated with disabling and potentially permanent serious adverse effects that can occur togeth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Antibiotics
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy, treatment and antibiotic prophylaxis, prevention of such infections. They may either bactericide, kill or bacteriostatic agent, inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the ones which cause the common cold or influenza. Drugs which inhibit growth of viruses are termed antiviral drugs or antivirals. Antibiotics are also not effective against fungi. Drugs which inhibit growth of fungi are called antifungal drugs. Sometimes, the term ''antibiotic''—literally "opposing life", from the Greek language, Greek roots ἀντι ''anti'', "against" and βίος ''bios'', "life"—is broadly used to refer to any substance used against ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
