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Glucotropaeolin
Glucotropaeolin or benzyl glucosinolate is a glucosinolate found in cruciferous vegetables, particularly garden cress. Upon enzymatic activity, it is transformed into benzyl isothiocyanate, which contributes to the characteristic flavor of these brassicas. Occurrence The compound was first reported in 1899, after its isolation from ''Tropaeolum majus'', a nasturtium species. Glucotropaeolin is now known to occur widely in other brassica, brassica families including Caricaceae, Phytolaccaceae, Resedaceae, Salvadoraceae and Tovariaceae. Structure The chemical structure of glucotropaeolin was confirmed by total synthesis in 1957. This showed that it is a glucose derivative with pyranose, β-D-glucopyranose configuration. At that time it was unclear whether the C=N bond was in the E–Z notation, Z form, with sulfur and oxygen substituents on the same side of the double bond, or the alternative E form in which they are on opposite sides. The suggestion was made that the Z form was mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucotropaeolin Unnatural E Isomer
Glucotropaeolin or benzyl glucosinolate is a glucosinolate found in cruciferous vegetables, particularly garden cress. Upon enzymatic activity, it is transformed into benzyl isothiocyanate, which contributes to the characteristic flavor of these brassicas. Occurrence The compound was first reported in 1899, after its isolation from ''Tropaeolum majus'', a nasturtium species. Glucotropaeolin is now known to occur widely in other brassica, brassica families including Caricaceae, Phytolaccaceae, Resedaceae, Salvadoraceae and Tovariaceae. Structure The chemical structure of glucotropaeolin was confirmed by total synthesis in 1957. This showed that it is a glucose derivative with pyranose, β-D-glucopyranose configuration. At that time it was unclear whether the C=N bond was in the E–Z notation, Z form, with sulfur and oxygen substituents on the same side of the double bond, or the alternative E form in which they are on opposite sides. The suggestion was made that the Z form was mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucosinolate
Glucosinolates are natural components of many pungent plants such as mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. These natural chemicals most likely contribute to plant defence against pests and diseases, and impart a characteristic bitter flavor property to cruciferous vegetables. Plants with glucosinolates Glucosinolates occur as secondary metabolites of almost all plants of the order Brassicales. Ordered in the Brassicales are for example the economically important family Brassicaceae as well as Capparaceae and Caricaceae. Outside of the Brassicales, the genera ''Drypetes'' and ''Putranjiva'' in the family Putranjivaceae, are the only other known occurrence of glucosinolates. Glucosinolates occur in various edible plants such as cabbage (white cabbage, Chinese cabbage, broccoli), Brussels sprouts, watercress, horseradish, capers, and radishes wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucosinolates
Glucosinolates are natural components of many pungency, pungent plants such as mustard plant, mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. These natural chemicals most likely contribute to plant defence against pests and Plant disease resistance, diseases, and impart a characteristic bitter (taste), bitter flavor property to cruciferous vegetables. Plants with glucosinolates Glucosinolates occur as secondary metabolites of almost all plants of the order (biology), order Brassicales. Ordered in the Brassicales are for example the economically important family Brassicaceae as well as Capparaceae and Caricaceae. Outside of the Brassicales, the genus, genera ''Drypetes'' and ''Putranjiva'' in the family Putranjivaceae, are the only other known occurrence of glucosinolates. Glucosinolates occur in various edible plants such as cabbage (white cabbage, Chines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucosinolates
Glucosinolates are natural components of many pungency, pungent plants such as mustard plant, mustard, cabbage, and horseradish. The pungency of those plants is due to mustard oils produced from glucosinolates when the plant material is chewed, cut, or otherwise damaged. These natural chemicals most likely contribute to plant defence against pests and Plant disease resistance, diseases, and impart a characteristic bitter (taste), bitter flavor property to cruciferous vegetables. Plants with glucosinolates Glucosinolates occur as secondary metabolites of almost all plants of the order (biology), order Brassicales. Ordered in the Brassicales are for example the economically important family Brassicaceae as well as Capparaceae and Caricaceae. Outside of the Brassicales, the genus, genera ''Drypetes'' and ''Putranjiva'' in the family Putranjivaceae, are the only other known occurrence of glucosinolates. Glucosinolates occur in various edible plants such as cabbage (white cabbage, Chines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brassicas
''Brassica'' () is a genus of plants in the cabbage and mustard family (Brassicaceae). The members of the genus are informally known as cruciferous vegetables, cabbages, or mustard plants. Crops from this genus are sometimes called ''cole crops''derived from the Latin ''caulis'', denoting the stem or stalk of a plant. The genus ''Brassica'' is known for its important agricultural and horticultural crops and also includes a number of weeds, both of wild taxa and escapees from cultivation. ''Brassica'' species and varieties commonly used for food include bok choy, broccoli, cauliflower, cabbage, choy sum, kohlrabi, napa cabbage, rutabaga, turnip and some seeds used in the production of canola oil and the condiment mustard. Over 30 wild species and hybrids are in cultivation, plus numerous cultivars and hybrids of cultivated origin. Most are seasonal plants ( annuals or biennials), but some are small shrubs. ''Brassica'' plants have been the subject of much scientific interest fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyranose
Pyranose is a collective term for saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom. There may be other carbons external to the ring. The name derives from its similarity to the oxygen heterocycle pyran, but the pyranose ring does not have double bonds. A pyranose in which the anomeric OH at C(l) has been converted into an OR group is called a pyranoside. Formation The pyranose ring is formed by the reaction of the hydroxyl group on carbon 5 (C-5) of a sugar with the aldehyde at carbon 1. This forms an intramolecular hemiacetal. If reaction is between the C-4 hydroxyl and the aldehyde, a furanose is formed instead. The pyranose form is thermodynamically more stable than the furanose form, which can be seen by the distribution of these two cyclic forms in solution. History Hermann Emil Fischer won the Nobel Prize in Chemistry (1902) for his work in determining the structure of the D-aldohexoses. How ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mustard Oil Bomb
The mustard oil bomb, formerly known as the glucosinolate–myrosinase complex, is a chemical herbivory defense system found in members of the Brassicaceae (or cabbage family). The mustard oil bomb requires the activation of a common plant secondary metabolite, glucosinolate, by an enzyme, myrosinase. The defense complex is typical among plant defenses to herbivory in that the two molecules are stored in different compartments in the leaves of plants until the leaf is torn by an herbivore. The glucosinolate has a β-glucose and a sulfated oxime. The myrosinase removes the β-glucose to form mustard oils that are toxic to herbivores. The defense system was named a "bomb" by Matile, because it like a real bomb is waiting to detonate upon disturbance of the plant tissue. Countermeasures There are many examples of biochemical adaptations to the mustard oil bomb. One occurs in the diamondback moth, ''Plutella xylostella''. This worldwide crop pest feeds exclusively on members of the Bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myrosinase
Myrosinase (, ''thioglucoside glucohydrolase'', ''sinigrinase'', and ''sinigrase'') is a family of enzymes involved in plant defense against herbivores, specifically the mustard oil bomb. The three-dimensional structure has been elucidated and is available in the PDB (see links in the infobox). A member of the glycoside hydrolase family, myrosinase possesses several similarities with the more ubiquitous O-glycosidases. However, myrosinase is the only known enzyme found in nature that can cleave a thio-linked glucose. Its known biological function is to catalyze the hydrolysis of a class of compounds called glucosinolates. Myrosinase activity Myrosinase is regarded as a defense-related enzyme and is capable of hydrolyzing glucosinolates into various compounds, some of which are toxic. Mechanism Myrosinase catalyzes the chemical reaction :a thioglucoside + H2O \rightleftharpoons a sugar + a thiol Thus, the two substrates of this enzyme are thioglucoside and H2O, whereas it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylalanine
Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino acid is classified as neutral, and nonpolar because of the inert and hydrophobic nature of the benzyl side chain. The L-isomer is used to biochemically form proteins coded for by DNA. Phenylalanine is a precursor for tyrosine, the monoamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), and the skin pigment melanin. It is encoded by the codons UUU and UUC. Phenylalanine is found naturally in the milk of mammals. It is used in the manufacture of food and drink products and sold as a nutritional supplement for its analgesic and antidepressant effects. It is a direct precursor to the neuromodulator phenethylamine, a commonly used dietary supplement. As an essential amino acid, phenylalanine is n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garden Cress
Cress (''Lepidium sativum''), sometimes referred to as garden cress (or curly cress) to distinguish it from Cress (other), similar plants also referred to as cress (from old Germanic ''cresso'' which means sharp, spicy), is a rather fast-growing, edible herb. Garden cress is genetically related to watercress and Mustard plant, mustard, sharing their peppery, tangy flavour and aroma. In some regions, garden cress is known as mustard and cress, garden pepper cress, pepperwort, pepper grass, or poor man's pepper.Staub, Jack E, Buchert, Ellen75 Exceptional Herbs for Your GardenPublished by Gibbs Smith, 2008. , 9781423602514 This annual plant can reach a height of , with many branches on the upper part. The white to pinkish flowers are only across, clustered in small branched racemes. When consumed raw, cress is a high-nutrient food containing substantial content of Vitamin A, vitamins A, Vitamin C, C and Vitamin K, K and several dietary minerals. In agriculture Garden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossen Rearrangement
The Lossen rearrangement is the conversion of a hydroxamate ester to an isocyanate. Typically O-acyl, sulfonyl, or phosphoryl O-derivative are employed. The isocyanate can be used further to generate ureas in the presence of amines or generate amines in the presence of H2O. Reaction mechanism The mechanism below begins with an O-acylated hydroxamic acid derivative that is treated with base to form an isocyanate that generates an amine and CO2 gas in the presence of H2O. The hydroxamic acid derivative is first converted to its conjugate base by abstraction of a hydrogen by a base. Spontaneous rearrangement releases a carboxylate anion to produce the isocyanate intermediate. The isocyanate is then hydrolyzed in the presence of H2O. Finally, the respective amine and CO2 are generated by abstraction of a proton with a base and decarboxylation. Hydroxamic acids are commonly synthesized from their corresponding esters. Historical references * * * See also *Curtius rearrangemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
E–Z Notation
''E''–''Z'' configuration, or the ''E''–''Z'' convention, is the IUPAC preferred method of describing the absolute stereochemistry of double bonds in organic chemistry. It is an extension of ''cis''–''trans'' isomer notation (which only describes ''relative stereochemistry'') that can be used to describe double bonds having two, three or four substituents. Following the Cahn–Ingold–Prelog priority rules (CIP rules), each substituent on a double bond is assigned a priority, then positions of the higher of the two substituents on each carbon are compared to each other. If the two groups of higher priority are on opposite sides of the double bond (''trans'' to each other), the bond is assigned the configuration ''E'' (from ''entgegen'', , the German word for "opposite"). If the two groups of higher priority are on the same side of the double bond (''cis'' to each other), the bond is assigned the configuration ''Z'' (from ''zusammen'', , the German word for "together" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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