Glucoside

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Chemical structure of decyl glucoside, a plant-derived glucoside used as a surfactant. Decyl-glucoside-2D-skeletal.png
Chemical structure of decyl glucoside, a plant-derived glucoside used as a surfactant.

A glucoside is a glycoside that is chemically derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes.

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The name was originally given to plant products of this nature, in which the other part of the molecule was, in the greater number of cases, an aromatic aldehydic or phenolic compound (exceptions are Jinigrin and Jalapin or Scammonin). It has now been extended to include synthetic ethers, such as those obtained by acting on alcoholic glucose solutions with hydrochloric acid, and also the polysaccharoses, e.g. cane sugar, which appear to be ethers also. Although glucose is the most common sugar present in glucosides, many are known which yield rhamnose or iso-dulcite; these may be termed pentosides. Much attention has been given to the non-sugar parts (aglyca) of the molecules; the constitutions of many have been determined, and the compounds synthesized; and in some cases the preparation of the synthetic glucoside effected. [1]

The simplest glucosides are the alkyl ethers which have been obtained by reacting hydrochloric acid on alcoholic glucose solutions. A better method of preparation is to dissolve solid anhydrous glucose in methanol containing hydrochloric acid. A mixture of alpha- and beta-methylglucoside results. [1]

The classification of glucosides is a matter of some intricacy. One method based on the chemical constitution of the non-glucose part of the molecules has been proposed that posits four groups: (I) alkyl derivatives, (2) benzene derivatives, (3) styrolene derivatives, and (4) anthracene derivatives. A group may also be constructed to include the cyanogenic glucosides, i.e. those containing prussic acid. Alternate classifications follow a botanical classification, which has several advantages; in particular, plants of allied genera contain similar compounds. In this article the chemical classification will be followed, and only the more important compounds will be discussed herein. [1]

Ethylene derivatives

These are generally mustard oils, which are characterized by a burning taste; their principal occurrence is in mustard and Tropaeolum seeds. Sinigrin, or the potassium salt of inyronic acid not only occurs in mustard seed, [2] but also in black pepper and in horseradish root. Hydrolysis with barium hydroxide, or decomposition by the ferment myrosin, gives glucose, allyl mustard oil and potassium hydroxide. Sinalbin occurs in white pepper; it decomposes to the mustard oil, glucose and sinapin, a compound of choline and sinapic acid. Jalapin or Scammonin occurs in scammony; it hydrolyses to glucose and jalapinolic acid. [1]

Benzene derivatives

These are generally oxy and oxyaldehydic compounds. [1]

Benzoic acid derivatives

The benzoyl derivative cellotropin has been used for tuberculosis. Populin, which occurs in the leaves and bark of Populus tremula, is benzoyl salicin. [1] Benzoyl-beta-D-glucoside is a compound found in the fern Pteris ensiformis .

Phenol derivatives

There are a number of glucosides found in natural phenols and polyphenols, as, for example, in the flavonoids chemical family. Arbutin, which occurs in bearberry along with methyl arbutin, hydrolyses to hydroquinone and glucose. Pharmacologically it acts as a urinary antiseptic and diuretic; Salicin, also termed Saligenin and glucose occurs in the willow. The enzymes ptyalin and emulsin convert it into glucose and saligenin, ortho-oxybenzylalcohol. Oxidation gives the aldehyde helicin. [1]

Styrolene derivatives

This group contains a benzene and also an ethylene group, being derived from styrolene. Coniferin, C16H22O8, occurs in the cambium of conifer wood. Emulsin converts it into glucose and coniferyl alcohol, while oxidation gives glycovanillin, which yields with emulsin, glucose and vanillin. Syringin, which occurs in the bark of Syringa vulgaris , is a methoxyconiferin. Phloridzus occurs in the root-bark of various fruit trees; it hydrolyses to glucose and phloretin, which is the phloroglucin ester of paraoxyhydratropic acid. It is related to the pentosides naringin, C27H32O14, which hydrolyses to rhamnose and naringenin, the phioroglucin ester of para-oxycinnamic acid, and hesperidin, which hydrolyses to rhamnose and hesperetin, the phloroglucin ester of meta-oxy-para-methoxycinnamic acid or isoferulic acid, C10H10O4. [3]

Anthracene derivatives

These are generally substituted anthraquinones; many have medicinal applications, being used as purgatives, while one, ruberythric acid, yields the valuable dyestuff madder, the base of which is alizarin. Chrysophanic acid, a dioxymethylanthraquinone, occurs in rhubarb, which also contains emodin, a trioxymethylanthraquinone; this substance occurs in combination with rhamnose in Frangula bark. [6]

Arguably the most important cyanogenic glucoside is amygdalin, which occurs in bitter almonds. The enzyme maltase decomposes it into glucose and mandelic nitrile glucoside; the latter is broken down by emulsin into glucose, benzaldehyde and prussic acid. Emulsin also decomposes amygdalin directly into these compounds without the intermediate formation of mandelic nitrile glucoside. [6]

Several other glucosides of this nature have been isolated. The saponins are a group of substances characterized by forming a lather with water; they occur in soap-bark. Mention may also be made of indican, the glucoside of the indigo plant; this is hydrolysed by the indigo ferment, indimulsiri, to indoxyl and indiglucin. [6]

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Benzoic acid is a white solid organic compound with the formula C6H5COOH, whose structure consists of a benzene ring with a carboxyl substituent. The benzoyl group is often abbreviated "Bz", thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –C6H5CO. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source.

<span class="mw-page-title-main">Hexose</span> 6-Carbon simple sugar

In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is C6H12O6, and their molecular weight is 180.156 g/mol.

<span class="mw-page-title-main">Glycoside</span> Molecule in which a sugar is bound to another functional group

In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme hydrolysis, which causes the sugar part to be broken off, making the chemical available for use. Many such plant glycosides are used as medications. Several species of Heliconius butterfly are capable of incorporating these plant compounds as a form of chemical defense against predators. In animals and humans, poisons are often bound to sugar molecules as part of their elimination from the body.

<span class="mw-page-title-main">Quercitron</span> Natural dye from the bark of the species Quercus velutina

Quercitron is a yellow natural dye obtained from the bark of the Eastern Black Oak, a forest tree indigenous in North America. It was formerly called Dutch pink, English pink, or Italian pink.

<span class="mw-page-title-main">Mucic acid</span> Chemical compound

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Phloroglucinol is an organic compound with the formula C6H3(OH)3. It is a colorless solid. It is used in the synthesis of pharmaceuticals and explosives. Phloroglucinol is one of three isomeric benzenetriols. The other two isomers are hydroxyquinol (1,2,4-benzenetriol) and pyrogallol (1,2,3-benzenetriol). Phloroglucinol, and its benzenetriol isomers, are still defined as "phenols" according to the IUPAC official nomenclature rules of chemical compounds. Many such monophenolics are often termed polyphenols.

<span class="mw-page-title-main">Hippuric acid</span> Chemical compound

Hippuric acid is a carboxylic acid and organic compound. It is found in urine and is formed from the combination of benzoic acid and glycine. Levels of hippuric acid rise with the consumption of phenolic compounds. The phenols are first converted to benzoic acid, and then to hippuric acid and excreted in urine.

<span class="mw-page-title-main">Glucosinolate</span> Class of chemical compounds

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.

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Rutin, also called rutoside, quercetin-3-O-rutinoside and sophorin, is the glycoside combining the flavonol quercetin and the disaccharide rutinose. It is a flavonoid found in a wide variety of plants, including citrus.

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Sinigrin or allyl glucosinolate is a glucosinolate that belongs to the family of glucosides found in some plants of the family Brassicaceae such as Brussels sprouts, broccoli, and the seeds of black mustard. Whenever sinigrin-containing plant tissue is crushed or otherwise damaged, the enzyme myrosinase degrades sinigrin to a mustard oil, which is responsible for the pungent taste of mustard and horseradish. Seeds of white mustard, Sinapis alba, give a less pungent mustard because this species contains a different glucosinolate, sinalbin.

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Kojic acid is an organic compound with the formula HOCH2C5H2O2OH. It is a derivative of 4-pyrone that functions in nature as a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine. It is a mild inhibitor of the formation of pigment in plant and animal tissues, and is used in food and cosmetics to preserve or change colors of substances. It forms a bright red complex with ferric ions.

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2-Pyrone (α-pyrone or pyran-2-one) is an unsaturated cyclic chemical compound with the molecular formula C5H4O2. It is isomeric with 4-pyrone.

<span class="mw-page-title-main">Phenolic content in wine</span> Wine chemistry

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 phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids.

<span class="mw-page-title-main">Caftaric acid</span> Chemical compound

Caftaric acid is a non-flavonoid phenolic compound.

The pyranoanthocyanins are a type of pyranoflavonoids. They are chemical compounds formed in red wines by yeast during fermentation processes or during controlled oxygenation processes during the aging of wine. The different classes of pyranoanthocyanins are carboxypyranoanthocyanins, methylpyranoanthocyanins, pyranoanthocyanin-flavanols, pyranoanthocyanin-phenols, portisins, oxovitisins and pyranoanthocyanin dimers; their general structure includes an additional ring that may have different substituents linked directly at C-10.

<span class="mw-page-title-main">Echinacoside</span> Chemical compound

Echinacoside is a natural phenol. It is a caffeic acid glycoside from the phenylpropanoid class. It is constituted from a trisaccharide consisting of two glucose and one rhamnose moieties glycosidically linked to one caffeic acid and one dihydroxyphenylethanol (hydroxytyrosol) residue at the centrally situated rhamnose. This water-soluble glycoside is a distinctive secondary metabolite of Echinacea angustifolia and Echinacea pallida but only occurs in trace amounts in Echinacea purpurea. It is also isolated from Cistanche spp.

<span class="mw-page-title-main">Glucotropaeolin</span> Chemical compound

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.

<i>Arthrobacter bussei</i> Species of bacterium

Arthrobacter bussei is a pink-coloured, aerobic, coccus-shaped, Gram-stain-positive, oxidase-positive and catalase-positive bacterium isolated from cheese made of cow´s milk. A. bussei is non-motile and does not form spores. Rod–coccus life cycle is not observed. Cells are 1.1–1.5 µm in diameter. On trypticase soy agar it forms pink-coloured, raised and round colonies, which are 1.0 mm in diameter after 5 days at 30 °C The genome of the strain A. bussei KR32T has been fully sequenced.

References

  1. 1 2 3 4 5 6 7 Chisholm 1911, p. 142.
  2. Jen, Jen-Fon; Lina, Tsai-Hung; Huang, Jenn-Wen; Chung, Wen-Chuan (2001). "Direct determination of sinigrin in mustard seed without desulfatation by reversed-phase ion-pair liquid chromatography". Journal of Chromatography A. 912 (2): 363–368. doi:10.1016/S0021-9673(01)00591-X. PMID   11330806.
  3. Chisholm 1911, pp. 142–142.
  4. Hogan, C. Michael (2008). Stromberg, N. (ed.). "Aesculus californica". Globaltwitcher.com. Archived from the original on 22 November 2012. Retrieved 22 October 2008.
  5. Keenan, George L. (1948). "Note on the microcrystallographic properties of rutin, quercitrin and quercetin". Journal of the American Pharmaceutical Association . 37 (11): 479. doi:10.1002/jps.3030371113.
  6. 1 2 3 4 Chisholm 1911, p. 143.

Further reading