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Phlorotannins
Phlorotannins are a type of tannins found in brown algae such as kelps and rockweeds or sargassacean species, and in a lower amount also in some red algae. Contrary to hydrolysable or condensed tannins, these compounds are oligomers of phloroglucinol (polyphloroglucinols). As they are called tannins, they have the ability to precipitate proteins. It has been noticed that some phlorotannins have the ability to oxidize and form covalent bonds with some proteins. In contrast, under similar experimental conditions three types of terrestrial tannins (procyanidins, profisetinidins, and gallotannins) apparently did not form covalent complexes with proteins. These phenolic compounds are integral structural components of cell walls in brown algae, but they also seem to play many other secondary ecological roles such as protection from UV radiation and defense against grazing. Biosynthesis and localization Most of the phlorotannins' biosynthesis is still unknown, but it appears they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrafucol A
Tetrafucol A is a fucol-type phlorotannin found in the brown algae ''Ascophyllum nodosum ''Ascophyllum nodosum'' is a large, common cold water seaweed or brown alga ( Phaeophyceae) in the family Fucaceae. Its common names include knotted wrack, egg wrack, feamainn bhuí, rockweed, knotted kelp and Norwegian kelp. It grows only in the ...'', '' Analipus japonicus'' and '' Scytothamnus australis''. In ''A. japonicus'', 5'-bromo- and 5'-chlorotetrafucol-A can also be detected. References Phlorotannins Natural phenol tetramers {{aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eckol
Eckol is a phlorotannin isolated from brown algae in the family Lessoniaceae such as species in the genus '' Ecklonia'' such as '' E. cava'' or '' E. kurome'' or in the genus '' Eisenia'' such as '' Eisenia bicyclis''. The molecule possesses a dibenzo-''p''-dioxin skeleton and a phloroglucinol component. The molecule can also be viewed as a phloroglucinol trimer. It exhibits an antiplasmin inhibitory effect and a radioprotective effect in a mouse model. It also exhibits an ''in vitro'' cytoprotective effect against oxidative stress in Chinese hamster lung fibroblasts. It also shows antithrombotic An antithrombotic agent is a drug that reduces the formation of blood clots ( thrombi).http://cancerweb.ncl.ac.uk/cgi-bin/omd?antithrombotic Antithrombotics can be used therapeutically for prevention ( primary prevention, secondary prevention) or ... and profibrinolytic activities. References {{phlorotannin Phlorotannins Dibenzodioxins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanillin–HCl Staining
Vanillin–HCl staining (10% vanillin and 90% of a mixture of ethanol and HCl, giving an orange color) can be used to visualize the localisation of tannins in cells. The localization of phlorotannins can be investigated by light microscopy after vanillin–HCl staining.Cytological studies on physodes in the vegetative cells of Cystoseira stricter Sauvagea (Phaeophyta, Fucales). Pellegrini L, J. Cell Sci., 1980, volume 41, pages 209–231 The phlorotannins can be seen this way in physodes in brown algae. The vanillin-HCl method can be used to estimate the proanthocyanidins content in plant cells, resulting in a red color of the test in the presence of catechin Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from ''catechu'', which is the tannic ... or proanthocyanidins. References Staining {{cell-biology-st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prussian Blue Assay
Prussian blue (also known as Berlin blue, Brandenburg blue, Parisian and Paris blue) is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It has the chemical formula . It consists of cations, where iron is in the oxidation state of +3, and anions, where iron is in the oxidation state of +2, so, the other name of this salt is iron(III) hexacyanoferrate(II). Turnbull's blue is essentially identical chemically, excepting that it has different impurities and particle sizes—because it is made from different reagents—and thus it has a slightly different color. Prussian blue was created in the early 18th century and is the first modern synthetic pigment. It is prepared as a very fine colloidal dispersion, because the compound is not soluble in water. It contains variable amounts of other ions and its appearance depends sensitively on the size of the colloidal particles. The pigment is used in paints, it became prominent in 19th-century () Japanese wood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ascorbic Acid
Ascorbic acid is an organic compound with formula , originally called hexuronic acid. It is a white solid, but impure samples can appear yellowish. It dissolves freely in water to give mildly acidic solutions. It is a mild reducing agent. Ascorbic acid exists as two enantiomers (mirror-image isomers), commonly denoted "" (for "levo") and "" (for "dextro"). The isomer is the one most often encountered: it occurs naturally in many foods, and is one form (" vitamer") of vitamin C, an essential nutrient for humans and many animals. Deficiency of vitamin C causes scurvy, formerly a major disease of sailors in long sea voyages. It is used as a food additive and a dietary supplement for its antioxidant properties. The "" form ( erythorbic acid) can be made by chemical synthesis, but has no significant biological role. Etymology The term ''ascorbic'' means antiscruvy and denotes the ability to fight off scurvy. It is related to combating Vitamin C deficiency. History The antiscor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine
Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated Polymer, polymeric chains, which show significant electrical conductivity. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Historically, pyridine was produced from coal tar. As of 2016, it is synthesized on the scale of about 20,000 tons per year worldwide. Properties Physical properties Pyridine is diamagnetism, diamagnetic. Its critical point (thermodynamics), critical parameters are: pressure 5.63 MPa, temperature 619 K and volume 248 cm3/mol. In the temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetic Anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the chemical formula, formula . Commonly abbreviated , it is one the simplest organic acid anhydride, anhydrides of a carboxylic acid and is widely used in the production of cellulose acetate as well as a reagent in organic synthesis. It is a colorless liquid that smells strongly of acetic acid, which is formed by its reaction with moisture in the air. Structure and properties Acetic anhydride, like most organic acid anhydrides, is a flexible molecule with a nonplanar structure. The C=O and C-O distances are 1.19 and 1.39 Å. The Pi bond, pi system linkage through the central oxygen offers very weak resonance stabilization compared to the dipole, dipole-dipole repulsion between the two carbonyl oxygens. The energy barriers to bond rotation between each of the optimal aplanar conformations are quite low. Production Acetic anhydride was first synthesized in 1852 by the French chemist Charles Frédéric Gerhardt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraction (chemistry)
Extraction in chemistry is a separation process consisting of the separation of a substance from a Matrix (chemical analysis), matrix. The distribution of a solute between two phases is an Chemical equilibrium, equilibrium condition described by partition theory. This is based on exactly how the analyte moves from the initial solvent into the extracting solvent. The term ''washing'' may also be used to refer to an extraction in which impurities are extracted from the solvent containing the desired Chemical compound, compound. Types of extraction * Liquid–liquid extraction ** Acid-base extraction ** Supercritical fluid extraction * Solid-liquid extraction ** Solid-phase extraction ** Maceration ** Ultrasound assisted extraction, Ultrasound-assisted extraction ** Microwave-assisted extraction ** Heat reflux extraction ** Instant controlled pressure drop extraction (:fr:Détente instantanée contrôlée, Détente instantanée contrôlée) * Perstraction Laboratory applica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Citrate
Lead citrate is a compound of lead and citrate that is primarily used as an enhancer for heavy metal staining in electron microscopy. This salt binds to osmium and uranyl acetate Uranyl acetate is the acetate salt of uranium oxide, a toxic yellow-green powder useful in certain laboratory tests. Structurally, it is a coordination polymer with formula UO2(CH3CO2)2(H2O)·H2O. Structure left, 260px, Structure (from X-ray ... and enhances contrast in many cellular structures. Lead citrate is highly reactive with carbon dioxide. References {{reflist Citrates Lead(II) compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranyl Acetate
Uranyl acetate is the acetate salt of uranium oxide, a toxic yellow-green powder useful in certain laboratory tests. Structurally, it is a coordination polymer with formula UO2(CH3CO2)2(H2O)·H2O. Structure left, 260px, Structure (from X-ray crystallography) of uranyl acetate dihydrate. Color code: red = O, gray = C, blue = U. In the polymer, uranyl (UO22+) centers are bridged by acetate ligands. The remainder of each (heptacoordinate) coordination sphere is provided by an aquo ligand and a bidentate acetate ligand. One water of crystallization occupies the lattice. Uranyl carboxylates are known for diverse carboxylic acids (formate, butyrate, acrylate). Uses Uranyl acetate is extensively used as a negative stain in electron microscopy."Negative Staining" University of Oxford [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
