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| Names | |
|---|---|
| IUPAC name 3,3′,4′,5,7-Pentahydroxyflavylium | |
| Systematic IUPAC name 2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-1λ4-benzopyran-1-ylium | |
| Other names Cyanidine 2-(3,4-Dihydroxyphenyl)chromenylium-3,5,7-triol | |
| Identifiers | |
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3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| E number | E163a(colours) |
| KEGG |
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| UNII |
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| Properties | |
| C15H11O6+ | |
| Molar mass | 287.24 g/mol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
| Cyanidin(pH indicator) | ||
| below pH 3 | above pH 11 | |
| 3 | ⇌ | 11 |
Cyanidin is a naturalorganic compound. It is a particular type ofanthocyanidin (glycoside version calledanthocyanins). It is a pigment found in many red berries includinggrapes,bilberry,blackberry,blueberry,cherry,chokeberry,cranberry,elderberry,hawthorn,loganberry,açai berry andraspberry.[1] It can also be found in other fruits such asapples andplums, and inred cabbage andred onion. It has a characteristic reddish-purple color, though this can change with pH; solutions of the compound are red at pH < 3, violet at pH 7-8, and blue at pH > 11. In certain fruits, the highest concentrations of cyanidin are found in the seeds and skin.[2] Cyanidin has been found to be a potentsirtuin 6 (SIRT6) activator.[3][4]
Cyanidin can be synthesized in berry plants through theshikimate pathway andpolyketide synthase (PKS) III. The shikimate pathway is a biosynthetic pathways that uses the starting materialsPhosphoenolpyruvic acid (PEP) andErythrose 4-phosphate to formshikimic acid, which then further reacts to form specificaromatic amino acids. L-phenylalanine, which is necessary in the production of cyanidin, is synthesized through the shikimate pathway.
In the synthesis of L-phenylalanine,chorismate undergoes aClaisen rearrangement by aChorismate mutase enzyme to formprephenate. Prephenate undergoes dehydration, decarboxylation, and transamination withPyridoxal phosphate (PLP) andalpha-Ketoglutaric acid to form L-phenylalanine (figure 1).
L-phenylalanine then undergoes an elimination of the primary amine withPhenylalanine ammonia-lyase (PAL) to form cinnamate. Through an oxidation with molecular oxygen andNADPH, a hydroxyl group is added to the para position of the aromatic ring. The compound then reacts withCoenzyme A (CoA), CoA ligase, andATP to attach CoA to the carboxylic acid group. The compound reacts withnaringenin-chalcone synthase and three malonyl CoA molecules to add six carbon atoms and three more keto groups ring throughPKS III.Aureusidin synthase catalyses the aromatization and cyclization of the newly added carbonyl groups and facilitates the release of CoA. The compound then spontaneously cyclizes to formnaringenin[7] (figure 2).
Naringenin is then converted to cyanidin through several oxidizing and reducing steps. First naringenin is reacted with two equivalents of oxygen,alpha-Ketogluteratic acid, and flavanone 3-hydroxylase to formdihydrokaempferol. The compound then reacts with NADPH and dihydroflavonol 4-reductase to formleucopelargonidin, which is further oxidized with oxygen,alpha-Ketogluteratic acid, and anthocyanidin synthase. This compound spontaneously loses a water molecule and a hydroxide ion to form cyanidin[8] (figure 3).
Among manyanthocyanidins studied, cyanidin most potently stimulated activity of thesirtuin 6 enzyme.[4]
Five anthocyanins were present in black raspberries: cyanidin 3-sambubioside, cyanidin 3-glucoside, cyanidin 3-xylosylrutinoside, cyanidin 3-rutinoside, and pelargonidin 3-rutinoside. Their identities and structures, with particular emphasis on cyanidin 3-xylosylrutinoside, were confirmed by NMR spectroscopy. Two of these anthocyanins, cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside, predominated, comprising 24-40 and 49-58%, respectively, of the total anthocyanins in black raspberries. On the basis of both potency and concentration, cyanidin 3-rutinoside and cyanidin 3-xylosylrutinoside were found to be the significant contributors to the antioxidant systems of black raspberries.
