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Flavones
Flavones (from Latin ''flavus'' "yellow") are a class of flavonoids based on the backbone of 2-phenylchromen-4-one (2-phenyl-1-benzopyran-4-one) (as shown in the first image of this article). Flavones are common in foods, mainly from spices, and some yellow or orange fruits and vegetables. Common flavones include apigenin (4',5,7-trihydroxyflavone), luteolin (3',4',5,7-tetrahydroxyflavone), tangeritin (4',5,6,7,8-pentamethoxyflavone), chrysin (5,7-dihydroxyflavone), and 6-hydroxyflavone. Intake and elimination The estimated daily intake of flavones is about 2 mg per day. Following ingestion and metabolism, flavones, other polyphenols, and their metabolites are absorbed poorly in body organs and are rapidly excreted in the urine, indicating mechanisms influencing their presumed absence of metabolic roles in the body. Drug interactions Flavones have effects on CYP (P450) activity, which are enzymes that metabolize most drugs in the body. Biosynthesis The biosynthesis of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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-phenyl chromen-4-one (3-phenyl-1,4-benzopyrone) structure *neoflavonoids, derived from 4-phenylcoumarine (4-phenyl-1,2-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 bioflavonoid have also been more loosely used to describe non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tangeritin
Tangeretin is an O- polymethoxylated flavone that is found in tangerine and other citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ... peels. Tangeretin strengthens the cell wall and acts as a plant's defensive mechanism against disease-causing pathogens.Uckoo, RM; et al. Sep. Purif. Technol. 2011. It has also been used as a marker compound to detect contamination in citrus juices. The following is a list of methods used to extract tangeretin from citrus peels: * column chromatography * preparative-high performance liquid chromatography * super critical fluid chromatography * high speed counter current chromatography * a combination of vacuum flash silica gel chromatography and flash C8 column chromatography * flash chromatography * isolation using ionic liquids and a cycle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavon Num
Flavon is a ''frazione'' of the ''comune'' (municipality) of Contà in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located about north of Trento Trento ( or ; Ladin and lmo, Trent; german: Trient ; cim, Tria; , ), also anglicized as Trent, is a city on the Adige River in Trentino-Alto Adige/Südtirol in Italy. It is the capital of the autonomous province of Trento. In the 16th centu .... It was an independent commune until 1 January 2016. References {{Authority control Frazioni of Trentino-Alto Adige/Südtirol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deamination
Deamination is the removal of an amino group from a molecule. Enzymes that catalyse this reaction are called deaminases. In the human body, deamination takes place primarily in the liver, however it can also occur in the kidney. In situations of excess protein intake, deamination is used to break down amino acids for energy. The amino group is removed from the amino acid and converted to ammonia. The rest of the amino acid is made up of mostly carbon and hydrogen, and is recycled or oxidized for energy. Ammonia is toxic to the human system, and enzymes convert it to urea or uric acid by addition of carbon dioxide molecules (which is not considered a deamination process) in the urea cycle, which also takes place in the liver. Urea and uric acid can safely diffuse into the blood and then be excreted in urine. Deamination reactions in DNA Cytosine Spontaneous deamination is the hydrolysis reaction of cytosine into uracil, releasing ammonia in the process. This can occur in vitro thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalcone
Chalcone is the organic compound C6H5C(O)CH=CHC6H5. It is an α,β-unsaturated ketone. A variety of important biological compounds are known collectively as chalcones or chalconoids. Chemical properties Chalcones have two absorption maxima at 280 nm and 340 nm. Synthesis Chalcone is usually prepared by an aldol condensation between benzaldehyde and acetophenone. : This reaction, which can be carried out without any solvent, is so reliable that it is used in as an example of green chemistry in undergraduate education. Biosynthesis Chalcones and chalconoids are synthesized in plants as secondary metabolites. The enzyme chalcone synthase, a type III polyketide synthase, is responsible for the biosynthesis of these compounds. The enzyme is found in all "higher" (vascular) and several "lower" ( non-vascular) plants. Potential pharmacology Chalcones and their derivatives demonstrate a wide range of biological activities including anti-inflammation. Some 2′-amino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claisen Condensation
The Claisen condensation is a carbon–carbon bond forming reaction that occurs between two esters or one ester and another carbonyl compound in the presence of a strong base, resulting in a β-keto ester or a β-diketone. It is named after Rainer Ludwig Claisen, who first published his work on the reaction in 1887. Requirements At least one of the reagents must be enolizable (have an α-proton and be able to undergo deprotonation to form the enolate anion). There are a number of different combinations of enolizable and nonenolizable carbonyl compounds that form a few different types of Claisen. The base used must not interfere with the reaction by undergoing nucleophilic substitution or addition with a carbonyl carbon. For this reason, the conjugate sodium alkoxide base of the alcohol formed (e.g. sodium ethoxide if ethanol is formed) is often used, since the alkoxide is regenerated. In mixed Claisen condensations, a non-nucleophilic base such as lithium diisopropylamide, or L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malonyl CoA
Malonyl-CoA is a coenzyme A derivative of malonic acid. Functions It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis. Fatty acid biosynthesis Malonyl-CoA provides 2-carbon units to fatty acids and commits them to fatty acid chain synthesis. Malonyl-CoA is formed by carboxylating acetyl-CoA using the enzyme acetyl-CoA carboxylase. One molecule of acetyl-CoA joins with a molecule of bicarbonate,Nelson D, Cox M (2008) ''Lehninger principles of biochemistry''. 5th Ed: p. 806 requiring energy rendered from ATP. Malonyl-CoA is utilised in fatty acid biosynthesis by the enzyme malonyl coenzyme A:acyl carrier protein transacylase (MCAT). MCAT serves to transfer malonate from malonyl-CoA to the terminal thiol of ''holo''-acyl carrier protein (ACP). Polyketide biosynthesis MCAT is also involved in bacterial polyketide biosynthesis. The enzyme MCAT together with an acyl carrier protein (ACP), and a polyketide synthase (PKS) and chain-length f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensation Reactions
In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a dehydration synthesis. However other molecules can also be lost, such as ammonia, ethanol, acetic acid and hydrogen sulfide. The addition of the two molecules typically proceeds in a step-wise fashion to the addition product, usually in equilibrium, and with loss of a water molecule (hence the name condensation). The reaction may otherwise involve the functional groups of the molecule, and is a versatile class of reactions that can occur in acidic or basic conditions or in the presence of a catalyst. This class of reactions is a vital part of life as it is essential to the formation of peptide bonds between amino acids and to the biosynthesis of fatty acids. Many variations of condensation reactions exist. Common examples include the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalcone Synthase
Chalcone synthase or naringenin-chalcone synthase (CHS) is an enzyme ubiquitous to higher plants and belongs to a family of polyketide synthase enzymes (PKS) known as type III PKS. Type III PKSs are associated with the production of chalcones, a class of organic compounds found mainly in plants as natural defense mechanisms and as synthetic intermediates. CHS was the first type III PKS to be discovered. It is the first committed enzyme in flavonoid biosynthesis. The enzyme catalyzes the conversion of 4-coumaroyl-CoA and malonyl-CoA to naringenin chalcone. Function CHS catalysis serves as the initial step for flavonoid biosynthesis. Flavonoids are important plant secondary metabolites that serve various functions in higher plants. These include pigmentation, UV protection, fertility, antifungal defense and the recruitment of nitrogen-fixing bacteria. CHS is believed to act as a central hub for the enzymes involved in the flavonoid pathway. Studies have shown that these enzyme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coumaroyl-CoA
Coumaroyl-coenzyme A is the thioester of coenzyme-A and coumaric acid. Coumaroyl-coenzyme A is a central intermediate in the biosynthesis of myriad natural products found in plants. These products include lignols (precursors to lignin and lignocellulose), flavonoids, isoflavonoids, coumarins, aurones, stilbenes, catechin, and other phenylpropanoids. Biosynthesis and significance It is generated in nature from phenylalanine, which is converted by PAL to trans-cinnamate. Trans-cinnamate is hydroxylated by trans-cinnamate 4-monooxygenase to give 4-hydroxycinnamate (i.e, coumarate). Coumarate is condensed with coenzyme-A in the presence of 4-coumarate-CoA ligase: :ATP + 4-coumarate + CoA \rightleftharpoons AMP + diphosphate + 4-coumaroyl-CoA. Enzymes using Coumaroyl-Coenzyme A * Anthocyanin 3-O-glucoside 6''-O-hydroxycinnamoyltransferase * Anthocyanin 5-aromatic acyltransferase * Chalcone synthase * 4-Coumarate-CoA ligase * 6'-Deoxychalcone synthase * Agmatine N4-coum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylate
In organic chemistry, a carboxylate is the conjugate base of a carboxylic acid, (or ). It is an ion with negative charge. Carboxylate salts are salts that have the general formula , where M is a metal and ''n'' is 1, 2,...; ''carboxylate esters'' have the general formula (or ). R and R′ are organic groups; R′ ≠ H. Synthesis Carboxylate ions can be formed by deprotonation of carboxylic acids. Such acids typically have p''K''a of less than 5, meaning that they can be deprotonated by many bases, such as sodium hydroxide or sodium bicarbonate. :RCOOH + NaOH -> RCOONa + H2O Resonance stabilization of the carboxylate ion Carboxylic acids easily dissociate into a carboxylate anion and a positively charged hydrogen ion (proton), much more readily than alcohols do (into an alkoxide ion and a proton), because the carboxylate ion is stabilized by resonance. The negative charge that is left after deprotonation of the carboxyl group is delocalized between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
