Cyanidin is a natural

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

. It is a particular type of

anthocyanidin Anthocyanidins are common plant pigments, the sugar-free counterparts of anthocyanins. They are based on the flavylium cation, an oxonium ion, with various groups substituted for its hydrogen atoms. They generally change color from red through ...

(

glycoside 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. ...

version called

anthocyanin Anthocyanins (), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart gave the name Anthokyan to a chemical com ...

s). It is a pigment found in many red berries including

grapes A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began perhaps 8,000 years ago, ...

bilberry Bilberries (), or sometimes European blueberries, are a primarily Eurasian species of low-growing shrubs in the genus '' Vaccinium'' (family Ericaceae), bearing edible, dark blue berries. The species most often referred to is ''Vaccinium myrti ...

blackberry The blackberry is an edible fruit produced by many species in the genus ''Rubus'' in the family Rosaceae, hybrids among these species within the subgenus ''Rubus'', and hybrids between the subgenera ''Rubus'' and ''Idaeobatus''. The taxonomy ...

blueberry Blueberries are a widely distributed and widespread group of perennial flowering plants with blue or purple berries. They are classified in the section ''Cyanococcus'' within the genus '' Vaccinium''. ''Vaccinium'' also includes cranberries ...

cherry A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour '' Prunus cerasus''. The n ...

, chokeberry,

cranberry Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus ''Oxycoccus'' of the genus '' Vaccinium''. In Britain, cranberry may refer to the native species '' Vaccinium oxycoccos'', while in North America, cranberry ...

, elderberry,

hawthorn Hawthorn or Hawthorns may refer to: Plants * '' Crataegus'' (hawthorn), a large genus of shrubs and trees in the family Rosaceae * ''Rhaphiolepis'' (hawthorn), a genus of about 15 species of evergreen shrubs and small trees in the family Rosace ...

, loganberry, açai berry and

raspberry The raspberry is the edible fruit of a multitude of plant species in the genus ''Rubus'' of the rose family, most of which are in the subgenus '' Idaeobatus''. The name also applies to these plants themselves. Raspberries are perennial with ...

. It can also be found in other fruits such as

apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...

s and

plum A plum is a fruit of some species in ''Prunus'' subg. ''Prunus'.'' Dried plums are called prunes. History Plums may have been one of the first fruits domesticated by humans. Three of the most abundantly cultivated species are not found ...

s, and in red cabbage and red 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. Cyanidin has been found to be a potent sirtuin 6 (SIRT6) activator.

List of cyanidin derivatives

* Antirrhinin (cyanidin-3-

rutinoside Rutinose is the disaccharide also known as 6-''O''-α-L- rhamnosyl-D-glucose (C12H22O10) that is present in some flavonoid glycosides. It is prepared from rutin by hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of wat ...

or 3-C-R), found in

black raspberry Black raspberry is a common name for three species of the genus ''Rubus'': *''Rubus leucodermis'', native to western North America *'' Rubus occidentalis'', native to eastern North America *''Rubus coreanus 300px, (left to right) ''R. corean ...

* Cyanidin-3-xylosylrutinoside, found in

* Cyanidin-3,4′-di-''O''-β-glucopyranoside, found in red onion * Cyanidin-4′-''O''-β-glucoside, found in red onion * Chrysanthemin (cyanidin-3-''O''-glucoside), found in

blackcurrant The blackcurrant (''Ribes nigrum''), also known as black currant or cassis, is a deciduous shrub in the family Grossulariaceae grown for its edible berries. It is native to temperate parts of central and northern Europe and northern Asia, whe ...

pomace * Ideain (cyanidin 3-O-galactoside), found in ''Vaccinium'' species * Cyanin ( cyanidin-3,5-O-diglucoside), found in

red wine Red wine is a type of wine made from dark-colored grape varieties. The color of the wine can range from intense violet, typical of young wines, through to brick red for mature wines and brown for older red wines. The juice from most purple gr ...

Biosynthesis

Cyanidin can be synthesized in berry plants through the shikimate pathway and

polyketide synthase Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynth ...

(PKS) III. The shikimate pathway is a biosynthetic pathways that uses the starting materials

Phosphoenolpyruvic acid Phosphoenolpyruvate (2-phosphoenolpyruvate, PEP) is the ester derived from the enol of pyruvate and phosphate. It exists as an anion. PEP is an important intermediate in biochemistry. It has the highest-energy phosphate bond found (−61.9 k ...

(PEP) and Erythrose 4-phosphate to form

shikimic acid Shikimic acid, more commonly known as its anionic form shikimate, is a cyclohexene, a cyclitol and a cyclohexanecarboxylic acid. It is an important biochemical metabolite in plants and microorganisms. Its name comes from the Japanese flower ''shik ...

, which then further reacts to form specific

aromatic amino acids An aromatic amino acid is an amino acid that includes an aromatic ring. Among the 20 standard amino acids, the following are classically considered aromatic: phenylalanine, tryptophan and tyrosine. Although histidine contains an aromatic ring, ...

. L-

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 amin ...

, which is necessary in the production of cyanidin, is synthesized through the shikimate pathway. In the synthesis of L-phenylalanine, chorismate undergoes a Claisen rearrangement by a

Chorismate mutase In enzymology, chorismate mutase () is an enzyme that catalyzes the chemical reaction for the conversion of chorismate to prephenate in the pathway to the production of phenylalanine and tyrosine, also known as the shikimate pathway. Hence, this ...

enzyme to form

prephenate Prephenic acid, commonly also known by its anionic form prephenate, is an intermediate in the biosynthesis of the aromatic amino acids phenylalanine and tyrosine, as well as of a large number of secondary metabolites of the shikimate pathway. It ...

. Prephenate undergoes dehydration, decarboxylation, and transamination with

Pyridoxal phosphate Pyridoxal phosphate (PLP, pyridoxal 5'- phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The International Union of Biochemistry and Molecular Biology has catalogued more than 140 PLP-dependent ...

(PLP) and alpha-Ketoglutaric acid to form L-phenylalanine (figure 1). Shikimate Pathway

L-phenylalanine then undergoes an elimination of the primary amine with Phenylalanine ammonia-lyase (PAL) to form cinnamate. Through an oxidation with molecular oxygen and

NADPH Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NA ...

, a hydroxyl group is added to the para position of the aromatic ring. The compound then reacts with

Coenzyme A Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All genomes sequenced to date encode enzymes that use coenzyme A as a subs ...

(CoA), CoA ligase, and ATP to attach CoA to the carboxylic acid group. The compound reacts with

naringenin Naringenin is a flavorless, colorless flavanone, a type of flavonoid. It is the predominant flavanone in grapefruit, and is found in a variety of fruits and herbs. Structure Naringenin has the skeleton structure of a flavanone with three hydro ...

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 ...

synthase and three malonyl CoA molecules to add six carbon atoms and three more keto groups ring through PKS III.

Aureusidin synthase Aureusidin synthase (, ''AmAS1'') is an enzyme with systematic name ''2',4,4',6'-tetrahydroxychalcone 4'-O-beta-D-glucoside:oxygen oxidoreductase''. Aureusidin synthase has two main enzymatic tasks: hydroxylation at the 3-position on the B-rin ...

catalyses the aromatization and cyclization of the newly added carbonyl groups and facilitates the release of CoA. The compound then spontaneously cyclizes to form

(figure 2). Naringenin synthesis

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 form

dihydrokaempferol Aromadendrin (aromodendrin or dihydrokaempferol) is a flavanonol, a type of flavonoid. It can be found in the wood of ''Pinus sibirica''. Metabolism The enzyme dihydrokaempferol 4-reductase uses ''cis''-3,4-leucopelargonidin and NADP+ to prod ...

. The compound then reacts with NADPH and dihydroflavinol 4-reductase to form

leucopelargonidin Leucopelargonidin is a colorless chemical compound related to leucoanthocyanins. It can be found in ''Albizia lebbeck'' (East Indian walnut), in the fruit of ''Anacardium occidentale'' (Cashew), in the fruit of ''Areca catechu'' (Areca nut), in th ...

, 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 cyanidinDewick, P. M. Medicinal Natural Products: A Biosynthetic Approach, 3rd ed.; John Wiley and Sons, Ltd: United Kingdom 2009; pp 137-186 (figure 3). Cyanidin synthesis

Activation

Among many

s studied, cyanidin most potently stimulated activity of the sirtuin 6 enzyme.

References

{{Anthocyanidins Anthocyanidins