Cyanidin: Structure, Where It Is Found, Benefits

The cyanidin is a chemical compound belonging to the group of anthocyanins. These bioactive compounds have the ability to reduce oxidative damage, as well as anti-inflammatory and anti-mutagenic properties, hence they are of interest in various pharmacological studies.

Additionally, anthocyanins possess characteristics of natural water-soluble colorants. These are responsible for the red, blue and purple pigmentation of plant products, such as fruits, flowers, stems, leaves, etc.

Cyanidin specifically gives rise to color in the fruits of plants such as magenta-grain Mexican corn, purple-pigmented red cabbage, and native Peruvian potatoes, whose pigments are red and purple respectively.

Currently, anthocyanins are being widely evaluated in the food industry, in favor of a possible substitution of synthetic dyes in food, by virtue of being harmless substances. That is, they do not cause adverse or harmful effects on the body.

In this sense, the incorporation of antiocyanins as food colorants is already allowed in some countries, provided that specific considerations for their use are met. 

For example, in the US only the use of the part that can be eaten of the plant is allowed, while in Mexico its use is established in specific foods, such as sausages, supplements and certain non-alcoholic beverages, among others.

Chemical structure

Cyanidin is also known by the name of cyanidol and its molecular formula is: C 15 H 11 O 6 .

Its chemical structure, like the other anthocyanins (pelargonidin, malvidin, petunidin, peonidin, delphinidin, among others) is composed of a flavone nucleus, defined by some authors as ring C and two aromatic rings (A and B).

The presence of these three rings with double bonds is what gives anthocyanins their pigmentation. Likewise, the definition of the type of anthocyanin is due to the variety of substituents at the 3, 4 and 5 carbon position of ring B.

In the structure of cyanidin, specifically the carbons in ring A and C are numbered from 2 to 8, while those of ring B go from 2 to 6. Therefore, when a hydroxyl radical is positioned in ring B carbon 3 and at carbon 5 a hydrogen, this change differentiates cyanidin from the rest of the anthocyanins.

Where is it located?

Cyanidin is prevalent in nature. Certain foods such as fruits, vegetables and vegetables have a high content of this compound.

This is confirmed by some studies, in which they have found a variety of cyanidin derivatives, including cyanidin-3-glucoside, as the most common derivative, mostly contained in cherries and raspberries.

Whereas, cyanidin-3-soforoside, cyanidin 3-glucorutinoside, cyanidin 3-rutinoside, cyanidin-3-arabinoside, cyanidin-3-malonyl-glucoside and cyanidin-3-malonylarabinoside, are less frequent; although malonil derivatives are present in greater quantity in red onion.

Likewise, high cyanidin content has been reported in strawberries, blueberries, grapes, blackberries, blackberries, plums, apples and pitahaya (dragon fruit). It should be noted that the highest concentration of cyanidin is found in fruit peels.

Additionally, its presence has been verified in the Mexican magenta grain corn, the tree tomato, in the fruit of the Colombian corozo (cyanidin-3-glucoside and cyanidin 3-rutinoside), and the pigmented native potatoes: blood of bull (cyanidin -3-glucoside) and wenq`os, both from Peru.

How does cyanidin work to determine pH?

Given its characteristics as a dye and its sensitivity to pH variations, cyanidin is used as an indicator in acid-base titrations. This is commonly extracted from the red cabbage or also called purple cabbage ( Brasica oleracea variante capitata f. Rubra ).

In acidic pH conditions, that is, as the pH drops (≤ 3), the cabbage leaves change color and turn red. This is due to the predominance of the flavillium cation in the cyanidin structure.

While, at neutral pH (7), the cabbage leaves maintain their blue-violet pigment, because a deprotonation occurs in the cyanidin structure, forming a blue quinoidal base.

On the contrary, if the pH conditions are alkaline, that is, the pH increases from 8 to 14, the color of the cabbage leaves turn towards green, yellow to colorless tones, by ionization of cyanidin, forming a molecule called chalcone.

This molecule is considered the end product of cyanidin degradation, therefore it cannot regenerate to cyanidin again.

Recent studies suggest its use in chemical laboratory practices as a substitute for conventional pH indicators. The purpose would be to reduce polluting waste for the environment.

Other factors that alter the properties of cyanidin

It should be noted that cyanidin loses its coloring property with heating of the solution, becoming colorless. This is because this compound is unstable at high temperatures.

Additionally, other factors, such as: light, oxygen, water activity, among others, are the main drawbacks for their incorporation into food effectively.

For this reason, it should be taken into account that cooking procedures in certain foods favor the loss of their antioxidant capacity, as is the case of the native Peruvian wenq`os potato, which decreases the cyanidin content when fried.

However, studies such as that of Ballesteros and Díaz 2017, are encouraging in this regard, since they have shown that conservation in sodium bisulfite at 1% w / v at a temperature of 4 ºC can improve the stability and durability of this indicator, prolonging in this way its useful life.

Likewise, its incorporation in dairy products has been tested, at pH <3 and stored at low temperatures for a short time, in order to preserve the stability of the molecule and therefore its properties.

Health benefits

In the group of anthocyanins, cyanidin is the most relevant, due to its wide distribution in a wide variety of fruits, in addition to the fact that its consumption has been shown to be safe and effective in the inhibition of reactive oxygen species, preventing the oxidative damage in various cells.

Therefore, cyanidin stands out for its extraordinary antioxidant potential, which makes it a possible biopharmaceutical in the prevention therapy of cancer cell proliferation (colon cancer and leukemia), mutations and tumors.

In addition, it has anti-inflammatory properties. Finally, it can reduce cardiovascular disease, obesity, and diabetes.

References

  1. Salinas Y, García C, Coutiño B, Vidal V. Variability in content and types of anthocyanins in blue / purple grains of Mexican corn populations. phytotec. mex. 2013; 36 (Suppl): 285-294. Available at: scielo.org.
  2. Castañeda-Sánchez A, Guerrero-Beltrán J. Pigments in red fruits and vegetables: Anthocyanins. Selected Topics of Food Engineering 2015; 9: 25-33. Available at: web.udlap.mx.
  3. Aguilera-Otíz M, Reza-Vargas M, Chew-Madinaveita R, Meza-Velázquez J. Functional properties of anthocyanins. 2011; 13 (2), 16-22. Available at: biotecnia.unison
  4. Torres A. Physical, chemical and bioactive characterization of ripe pulp of tree tomato ( Cyphomandra betacea ) (Cav.) Sendt. ALAN. 2012; 62 (4): 381-388. Available at: scielo.org/
  5. Rojano B, Cristina I, Cortes B. Stability of anthocyanins and oxygen radical absorbance capacity (ORAC) values ​​of aqueous extracts of corozo ( Bactris guineensis ). Rev Cubana Plant Med . 2012; 17 (3): 244-255. Available at: sld.cu/scielo
  6. Barragan M, Aro J. Determination of the effect of cooking processes in pigmented native potatoes ( Solanum tuberosum spp. Andigena ) on their bioactive compounds. investigated. Altoandin . 2017; 19 (1): 47-52. Available in: scielo.org.
  7. Heredia-Avalos S. Surprising chemistry experiences with homemade pH indicators. Eureka Magazine on Science Teaching and Dissemination . 2006; 3 (1): 89-103. Available at: redalyc.org/
  8. Soto A, Castaño T. Study of the encapsulation of anthocyanins with the sol-gel technique for their application as food coloring [Master’s Thesis]. Autonomous University of Querétaro, Querétaro; 2018.Available at: ri-ng.uaq.mx
  9. Ballesteros F, Díaz B, Herrera H, Moreno R. Anthocyanin as a substitute for synthetic pH indicators: a step towards green products [Environmental Engineering Thesis]. Universidad de la Costa CUC, Barranquilla, Colombia; 2017.

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