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Umbellic Acid
Umbellic acid (2,4-dihydroxycinnamic acid) is a hydroxycinnamic acid. It is an isomer of caffeic acid. It is a precursor in the umbelliferone biosynthesis pathway. Umbelliferone is a phenylpropanoid and as such is synthesized from L-phenylalanine, which in turn is produced via the shikimate pathway. Phenylalanine is lysated into cinnamic acid, followed by hydroxylation by cinnamate 4-hydroxylase to yield 4-coumaric acid. The 4-coumaric acid is again hydroxylated by cinnamate/coumarate 2-hydroxylase to yield 2,4-dihydroxy-cinnamic acid followed by a bond rotation of the unsaturated bond adjacent to the carboxylic acid group. Finally an intramolecular attack from the hydroxyl group of C2' to the carboxylic acid group closes the ring and forms the lactone Lactones are cyclic carboxylic esters. They are derived from the corresponding hydroxycarboxylic acids by esterification. They can be saturated or unsaturated. Lactones are formed by lactonization, the intramolecular esterificat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxycinnamic Acid
Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. These compounds are hydroxy derivatives of cinnamic acid. In the category of List of phytochemicals in food, phytochemicals that can be found in food, there are: * alpha-Cyano-4-hydroxycinnamic acid, α-Cyano-4-hydroxycinnamic acid * Caffeic acid – burdock, hawthorn, artichoke, pear, basil, thyme, oregano, apple * Cichoric acid * Cinnamic acid – aloe * Chlorogenic acid – echinacea, strawberries, pineapple, coffee, sunflower, blueberries * Diferulic acids * Coumaric acid * Ferulic acid (3-methoxy-4-hydroxycinnamic acid) – oats, rice, artichoke, orange, pineapple, apple, peanut * Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid or sinapic acid) Hydroxycinnamoyltartaric acids * Caftaric acid – grapes and wine, mainly the trans isomer, ''trans'' isomer * Coutaric acid – grapes and wine, both ''trans'' and ''cis'' isomers * Fertaric acid – grapes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactone
Lactones are cyclic carboxylic esters. They are derived from the corresponding hydroxycarboxylic acids by esterification. They can be saturated or unsaturated. Lactones are formed by lactonization, the intramolecular esterification of the corresponding hydroxycarboxylic acids. Nomenclature Greek alphabet#Letters, Greek prefixes in alphabetical order indicate ring size. Lactones are usually named according to the precursor acid molecule (''aceto'' = 2 carbon atoms, ''propio'' = 3, ''butyro'' = 4, ''valero'' = 5, ''capro'' = 6, etc.), with a ''-lactone'' suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH and the -COOH groups along said backbone. The first carbon atom after the carbon in the -COOH group on the parent compound is labelled α, the second will be labeled β, and so forth. Therefore, the prefixes also indicate the size of the lactone ring: α-lactone = 3-membered ring, β-lac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroxycinnamic Acids
Hydroxycinnamic acids (hydroxycinnamates) are a class of aromatic acids or phenylpropanoids having a C6–C3 skeleton. These compounds are hydroxy derivatives of cinnamic acid. In the category of phytochemicals that can be found in food, there are: * α-Cyano-4-hydroxycinnamic acid * Caffeic acid – burdock, hawthorn, artichoke, pear, basil, thyme, oregano, apple * Cichoric acid * Cinnamic acid – aloe * Chlorogenic acid – echinacea, strawberries, pineapple, coffee, sunflower, blueberries * Diferulic acids * Coumaric acid * Ferulic acid (3-methoxy-4-hydroxycinnamic acid) – oats, rice, artichoke, orange, pineapple, apple, peanut * Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid or sinapic acid) Hydroxycinnamoyltartaric acids * Caftaric acid – grapes and wine, mainly the ''trans'' isomer * Coutaric acid Coutaric acid is a hydroxycinnamoyltartaric acid found in wine, pomace and grape. It is an ester formed from coumaric acid and tartaric acid Tartaric acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klebsiella Oxytoca
''Klebsiella oxytoca'' is a Gram-negative, rod-shaped bacterium that is closely related to '' K. pneumoniae'', from which it is distinguished by being indole-positive; it also has slightly different growth characteristics in that it is able to grow on melezitose, but not 3-hydroxybutyrate. It was first described in 1886 when it was isolated from sour milk and named ''Bacillus oxytocus perniciosus'' (from Greek ''oxus'' 'sour' + ''-tokos'' 'producing'). ''Klebsiella oxytoca'' is characterized by negative methyl red, positive VP, positive citrate, urea and TSI gas production, is AA, and negative for TSI sulfide, DNAse, growth on sulfide-indole motility medium and the phenylalanine deaminase test. It is a diazotroph, able to colonise plant hosts and fix atmospheric nitrogen into a form which the plant can use. Association of ''K. oxytoca'' with the barley rhizosphere during an entire vegetative period has been demonstrated. The bacteria adhere strongly to root hairs, and less stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-hydroxycinnamate Decarboxylase
4-Hydroxycinnamate decarboxylase is an enzyme that uses ''p''-coumaric acid to produce 4-ethylphenol. ''p''-Coumaric acid is the precursor of 4-ethylphenol produced by the yeast ''Saccharomyces'' and ''Brettanomyces'' in wine. The yeast converts this to 4-vinylphenol via the enzyme cinnamate decarboxylase. 4-Hydroxycinnamate decarboxylase can also be induced in bacteria species such as ''Klebsiella oxytoca'' and works also with p-coumaric acid analogs such as caffeic acid, ferulic acid and E- 2,4-dihydroxycinnamic acid. References See also * Wine chemistry Wine is a complex mixture of chemical compounds in a hydro-alcoholic solution with a pH around 4. The chemistry of wine and its resultant quality depend on achieving a balance between three aspects of the berries used to make the wine: their sugar ... {{enzyme-stub Hydroxycinnamic acids metabolism EC 4.1.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbelliferone
Umbelliferone, also known as 7-hydroxycoumarin, hydrangine, skimmetine, and ''beta''-umbelliferone, is a natural product of the coumarin family. It absorbs ultraviolet light strongly at several wavelengths. There are some indications that this chemical is antimutagenic, it is used in sunscreens. Umbelliferone has been reported to have antioxidant properties. It is a yellowish-white crystalline solid that has a slight solubility in hot water, but high solubility in ethanol. Natural occurrences and name Umbelliferone's name is from the umbelliferae family of plants, and the plant family in turn was named for their umbrella-shaped inflorescences, each called an umbel. Umbelliferone occurs in many familiar plants from the Apiaceae (Umbelliferae) family such as carrot, coriander and garden angelica, as well as in plants from other families, such as the mouse-ear hawkweed (''Hieracium pilosella'', Asteraceae) or the bigleaf hydrangea (''Hydrangea macrophylla'', Hydrangeaceae, under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboxylic Acid
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl group (e.g., alkyl, alkenyl, aryl), or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion. Examples and nomenclature Carboxylic acids are commonly identified by their trivial names. They often have the suffix ''-ic acid''. IUPAC-recommended names also exist; in this system, carboxylic acids have an ''-oic acid'' suffix. For example, butyric acid () is butanoic acid by IUPAC guidelines. For nomenclature of complex molecules containing a carboxylic acid, the carboxyl can be considered position one of the parent chain even if there are other substituents, such as 3-chloropropanoic acid. Alternately, it can be named ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caffeic Acid
Caffeic acid is an organic compound with the formula . It is a polyphenol with a key role in scavenging reactive oxygen species (ROS) generated in energy metabolism. Caffeic acid is also one major polyphenol responsible for maintaining normal levels of nitric oxide (NO) within cells. Caffeic acid is a yellow, solid chemical compound that is structually classified as a hydroxycinnamic acid, and the molecule consists of both phenolic and acrylic functional groups. Caffeic acid is found in all plants as an intermediate in the biosynthesis of lignin, a naturally occurring complex carbohydrate representing the principal components of biomass and its residues. It is chemically unrelated to caffeine; instead, the shared name is related to its presence in coffee. Natural occurrences Caffeic acid can be found in the bark of ''Eucalyptus globulus'' the barley grain ''Hordeum vulgare'' and the herb '' Dipsacus asperoides''. It can also be found in the freshwater fern '' Salvinia molest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
