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B Type Proanthocyanidin
B type proanthocyanidins are a specific type of proanthocyanidin, which are a class of flavanoids. They are oligomers of flavan-3-ols. Dimeric B type proanthocyanidins These molecules have the molecular formula C30H26O12 (molar mass : 578.52 g/mol, exact mass : 578.142426). Molecules with 4→8 bonds The 4-8 bond can be in the alpha or in the beta position. * Procyanidin B1 or epicatechin-(4β→8)-catechin * Procyanidin B2 or (−)-epicatechin-(4β→8)-(−)-epicatechin * Procyanidin B3 or catechin-(4α→8)-catechin * Procyanidin B4 or catechin-(4α→8)-epicatechin Molecules with 4→6 bonds * Procyanidin B5 or epicatechin-(4β→6)-epicatechin * Procyanidin B6 or catechin-(4α→6)-catechin * Procyanidin B8 or catechin-(4α→6)-epicatechin Chemistry B-type procyanidin (catechin dimer) can be converted to A-type procyanidin by radical oxidation. Dimeric proanthocyanidins can also be synthesized with procyanidin-rich grape seed extracts reacted with flavan-3-ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proanthocyanidin
Proanthocyanidins are a class of polyphenols found in many plants, such as cranberry, blueberry, and grape seeds. Chemically, they are oligomeric flavonoids. Many are oligomers of catechin and epicatechin and their gallic acid esters. More complex polyphenols, having the same polymeric building block, form the group of tannins. Proanthocyanidins were discovered in 1947 by Jacques Masquelier, who developed and patented techniques for the extraction of oligomeric proanthocyanidins from pine bark and grape seeds. Often associated with prevention of urinary tract infections (UTIs) by consuming cranberries, grape seeds or red wine, proanthocyanidins have not been conclusively shown as effective for preventing or treating UTIs. Distribution in plants Proanthocyanidins, including the lesser bioactive and bioavailable polymers (four or more catechins), represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins. They can be found in many plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin B8
Procyanidin B8 is a B type proanthocyanidin. Procyanidin B8 is a catechin-(4α→6)-epicatechin 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 ... dimer. It can be found in grape seedsProcyanidin dimers and trimers from grape seeds. Jorge M. Ricardo da Silva, Jacques Rigaud, Véronique Cheynier, Annie Cheminat and Michel Moutounet,Phytochemistry, 1991, Volume 30, Issue 4, Pages 1259–1264, and in beer.Structure elucidation of proanthocyanidins: Direct synthesis and isolation from Pilsener beer. Jan Delcour, Thesis, 1985 References Procyanidin dimers {{Aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin B3
Procyanidin B3 is a B type proanthocyanidin. Procyanidin B3 is a catechin dimer (catechin-(4α→8)-catechin). Natural occurrences It can be found in red wine, in barley, in beer, in peach or in '' Jatropha macrantha'', the Huanarpo Macho. Health effects It has been identified as a hair-growth stimulant. Chemical synthesis Molar equivalents of synthetic (2R,3S,4R or S)- leucocyanidin and (+)-catechin condense with exceptional rapidity at pH 5 under ambient conditions to give the all-trans- ,8 and ,6bi- +)-catechins(procyanidins B3, B6) the all-trans- ,8:4,8 and ,8:4,6tri- +)-catechins(procyanidin C2 and isomer). See also * Phenolic content in wine The phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include ... References Procyanidin dimers {{Aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boronic Acid
A boronic acid is an organic compound related to boric acid () in which one of the three hydroxyl groups () is replaced by an alkyl or aryl group (represented by R in the general formula ). As a compound containing a carbon–boron bond, members of this class thus belong to the larger class of organoboranes. Boronic acids act as Lewis acids. Their unique feature is that they are capable of forming reversible covalent complexes with sugars, amino acids, hydroxamic acids, etc. (molecules with vicinal, (1,2) or occasionally (1,3) substituted Lewis base donors (alcohol, amine, carboxylate)). The p''K''a of a boronic acid is ~9, but they can form tetrahedral boronate complexes with p''K''a ~7. They are occasionally used in the area of molecular recognition to bind to saccharides for fluorescent detection or selective transport of saccharides across membranes. Boronic acids are used extensively in organic chemistry as chemical building blocks and intermediates predominantly in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin C2
Procyanidin C2 is a B type proanthocyanidin trimer, a type of condensed tannin. Natural occurrences Procyanidin C2 is found in grape seeds (''Vitis vinifera'') and wine, in barley (''Hordeum vulgare''), malt and beer, in ''Betula spp.'', in ''Pinus radiata'', in '' Potentilla viscosa'', in ''Salix caprea'' or in ''Cryptomeria japonica''. The contents in barley grain of trimeric proanthocyanidins, including procyanidin C2, range from 53 to 151 μg catechin equivalents/g. Possible health uses Proanthocyanidin oligomers, extracted from grape seeds, have been used for the experimental treatment of androgenic alopecia. When applied topically, they promote hair growth ''in vitro'', and induce anagen ''in vivo''. Procyanidin C2 is the subtype of extract most effective. Experiments showed that both procyanidin C2 and Pycnogenol (French maritime pine bark extract) increase TNF-α secretion in a concentration- and time-dependent manner. These results demonstrate that procyanidins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Tetrafluoroborate
Silver tetrafluoroborate is an inorganic compound with the chemical formula AgBF4. It is a white solid that dissolves in polar organic solvents as well as water. In its solid state, the Ag+ centers are bound to fluoride. Preparation Silver tetrafluoroborate is prepared by the reaction between boron trifluoride and silver oxide in the presence of benzene. Laboratory uses In the inorganic and organometallic chemistry laboratory, silver tetrafluoroborate, sometimes referred to "silver BF-4", is a useful reagent. In dichloromethane, silver tetrafluoroborate is a moderately strong oxidant. Similar to silver hexafluorophosphate, it is commonly used to replace halide anions or ligands with the weakly coordinating tetrafluoroborate anions. The abstraction of the halide is driven by the precipitation of the appropriate silver halide A silver halide (or silver salt) is one of the chemical compounds that can form between the element silver (Ag) and one of the halogens. In particular, br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver Trifluoromethanesulfonate
Silver trifluoromethanesulfonate, or silver triflate is the triflate (CF3SO3−) salt of Ag+. It is a white or colorless solid that is soluble in water and some organic solvents including, benzene. It is a reagent used in the synthesis of organic and inorganic triflates. Synthesis An early preparation method starts from the barium salt of trifluoromethanesulfonic acid (TfOH), from which the free TfOH is formed with dilute sulfuric acid, which is then neutralized with silver carbonate (Ag2CO3). :Ba^2+ SO2CF3 -> ce-\ce] CF3SO2OH -> ceCF3SO2O^- Ag+ The silver triflate is thereby obtained in a yield of 95% and can be recrystallized from benzene/tetrachloromethane or ether/tetrachloromethane Carbon tetrachloride, also known by many other names (such as tetrachloromethane, also recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVACR) is an organic compound with the chemica ... for purification. In an improved vers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin C2
Procyanidin C2 is a B type proanthocyanidin trimer, a type of condensed tannin. Natural occurrences Procyanidin C2 is found in grape seeds (''Vitis vinifera'') and wine, in barley (''Hordeum vulgare''), malt and beer, in ''Betula spp.'', in ''Pinus radiata'', in '' Potentilla viscosa'', in ''Salix caprea'' or in ''Cryptomeria japonica''. The contents in barley grain of trimeric proanthocyanidins, including procyanidin C2, range from 53 to 151 μg catechin equivalents/g. Possible health uses Proanthocyanidin oligomers, extracted from grape seeds, have been used for the experimental treatment of androgenic alopecia. When applied topically, they promote hair growth ''in vitro'', and induce anagen ''in vivo''. Procyanidin C2 is the subtype of extract most effective. Experiments showed that both procyanidin C2 and Pycnogenol (French maritime pine bark extract) increase TNF-α secretion in a concentration- and time-dependent manner. These results demonstrate that procyanidins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin C1
Procyanidin C1 (PCC1) is a B type proanthocyanidin. It is an epicatechin trimer found in grape (''Vitis vinifera''), unripe apples, and cinnamon. Natural occurrence and function Procyanidin C1 can be isolated from grape seed extract. Chemical synthesis The stereoselective synthesis of seven benzylated proanthocyanidin trimers (epicatechin-(4β-8)-epicatechin-(4β-8)-epicatechin trimer (procyanidin C1), catechin-(4α-8)-catechin-(4α-8)-catechin trimer (procyanidin C2), epicatechin-(4β-8)-epicatechin-(4β-8)-catechin trimer and epicatechin-(4β-8)-catechin-(4α-8)-epicatechin trimer derivatives) can be achieved with Trimethylsilyl trifluoromethanesulfonate, TMSOTf-catalyzed condensation reaction, in excellent yields. The structure of benzylated procyanidin C2 was confirmed by comparing the 1H NMR spectra of protected procyanidin C2 that was synthesized by two different condensation approaches. Finally, deprotection of (+)-catechin and (-)-epicatechin trimers derivatives gives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Type Proanthocyanidin
A type proanthocyanidins are a specific type of proanthocyanidins, which are a class of flavonoid. Proanthocyanidins fall under a wide range of names in the nutritional and scientific vernacular, including oligomeric proanthocyanidins, flavonoids, polyphenols, condensed tannins, and OPCs. Proanthocyanidins were first popularized by French scientist Jacques Masquelier. Distribution in plants A-type linkage is a less common feature in proanthocyanidins with both 4β→8 ( B-type) and 2β→O→7 interflavanoid bonds. A-type proanthocyanidin glycosides can be isolated from cocoa liquor. Dimers * Procyanidin A1 is an epicatechin-(2β→7,4β→8)-catechin dimer. * Procyanidin A2 is a dimeric (-)epicatechin. Other A-type proanthocyanidins can be found in cranberries, cinnamon, peanut skins and ''Geranium niveum''. Chemistry B-type procyanidins (catechin dimers) can be converted to A-type procyanidins by radical oxidation. Fragmentation patterns for A-type proanthocyanidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 juice or boiled extract of ''Mimosa catechu'' (''Acacia catechu'' L.f). Chemistry Catechin possesses two benzene ring Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atom ...s (called the A- and B-rings) and a dihydropyran heterocycle (the C-ring) with a hydroxyl group on carbon 3. The A-ring is similar to a resorcinol moiety while the B-ring is similar to a catechol moiety. There are two chirality (chemistry), chiral centers on the molecule on carbons 2 and 3. Therefore, it has four diastereoisomers. Two of the isomers are in trans configura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyanidin B6
Procyanidin B6 is a B type proanthocyanidin. Procyanidin B6 is a catechin-(4α→6)-catechin dimer. It can be found in grape seeds and in beer. Chemical synthesis Molar equivalents of synthetic (2R,3S,4R or S)- and (+)- condense with exceptional rapidity at pH 5 under ambient conditions to give the all-trans- ,8 and ,6bi- +)-catechins([...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
