Flavonoids and carotenoids. Radiant and healthy skin tone without cosmetics and solarium: carotenoids

To the group of carotenoids include substances that are colored yellow or orange. The most famous representatives of carotenoids are carotenes - pigments that give a specific color to the roots of carrots, as well as lutein - a yellow pigment contained along with carotenes in the green parts of plants. The color of yellow corn seeds depends on the carotenes and carotenoids they contain, called zeaxanthin and cryptoxanthin. The color of tomato fruits is due to the carotenoid lycopene. Carotenoids play an important role in the metabolism of plants, participating in the process of photosynthesis.

The group of carotenoids includes about 65-70 natural pigments. Carotenoids are found in most plants (with the exception of some fungi). Probably in all animal organisms, but their concentration is almost always very low. The content of carotenoids in green leaves is approximately 0.07-0.2% based on the dry weight of the leaves. In some exceptional cases, however, a very high concentration of carotenoids is observed. For example, the anthers of many lily species contain very high amounts of lutein and a carotenoid called antheraxanthin. One of the characteristic features of carotenoids is the presence in them of a significant number of conjugated double bonds that form their chromophore groups, on which color depends. All natural carotenoids can be considered as derivatives lycopene- a carotenoid found in the fruits of tomatoes, as well as in some berries and fruits. Empirical formula lycopene C40H56.

By forming a ring at one or both ends of the lycopene molecule, its isomers are formed: alpha-, beta- or gamma-carotenes. Comparing the formulas, it can be seen that alpha-carotene differs from the beta-isomer by the position of the double bond in one of the cycles located at the ends of the molecule. Unlike alpha and beta isomers, gamma-carotene has only one cycle.

Plants rich in carotenoids

The green parts of plants and the carrot root are richest in carotenes.

Natural carotenoids - derivatives of carotene and lycopene

Carotenes are the substances from which vitamin A is formed. Since lycopene and carotenes contain 40 carbon atoms, they can be considered as being formed by eight isoprene residues. Without exception, all other natural carotenoids are derivatives of the four above hydrocarbons: lycopene and carotenes. They are formed from these hydrocarbons by introducing: hydroxyl, carbonyl or methoxy groups, or by partial hydrogenation or oxidation. As a result of the introduction of two hydroxy groups into the beta-carotene molecule, a carotenoid is formed, which is contained in corn grain and is called zeaxanthin. С40Н56О2. The introduction of two hydroxy groups into the alpha-carotene molecule leads to the formation of lutein C40H56O2 (3,3-dioxy-alpha-carotene), an isomer of zeaxanthin, which is found along with carotenes in the green parts of plants. As a result of the addition of one oxygen atom to the beta-carotene molecule with the formation of a furanoid structure, the carotenoid citroxanthin C40H56O is obtained, which is contained in the peel of citrus fruits. The oxidation products of carotenoids containing 40 carbon atoms in a molecule are C20H2404 crocetin, C25H30O4 bixin, and C30H40O2 beta-citraurine. Crocetin is a coloring matter contained in the stigmas of crocus in combination with two molecules of disaccharide gentiobiose in the form of crocin glycoside. Bixin is a red pigment found in the fruits of the tropical plant Bixa orellana; used for tinting butter, margarine and other food products. Brown algae contain the carotenoid fucoxanthin C40H60O6, which takes part in the process of photosynthesis as a so-called auxiliary pigment.

The role of carotenoids in the human body

In the body of animals and humans, carotenoids play an important role as starting substances from which vitamins of group A are formed, as well as "visual purple" involved in the visual act. In plants, carotenoids play an important role in the process of photosynthesis. Based on the chemical structure of carotenoids containing a significant amount of double bonds, it can be assumed that they are carriers of active oxygen in the plant and take part in redox processes. This is indicated by the wide distribution in plants of oxygen derivatives of carotenoids - epoxides, which give up their oxygen extremely easily. Carotenoids easily form peroxides, in which an oxygen molecule is added at the double bond site and can then easily oxidize various substances.

From yellow to red-orange, synthesized by bacteria, algae, fungi, higher plants, some sponges, corals and other organisms; determine the color of flowers and fruits. They are polyunsaturated. conn. terpene series, constructed preim. according to a single structural principle: at the ends of the polyene chain, consisting of 4 isoprenoid residues, cyclohexene rings are located, or aliphatic. isoprenoid residues. In most cases, they contain 40 carbon atoms in a molecule. They are divided into carotenoids, C 40 xanthophylls, homo-, apo- and nor-K. Holy Islands of some K. are given in the table. From grows. materials K. can be isolated by extraction org. solutions, not containing peroxides, in scattered light in an inert atmosphere with the last. saponification and chromatography. separation. Carotenoid hydrocarbons (carotenes) max. widely present in higher plants. The main ones are b-, a-, g-, e-carotees and lycopene (f-ly I a- Idcorresponding). All of them are well sol. in CHCl 3 , CS 2 and benzene, worse - in ether, hexane, fats and oils. Easily attach O 2 air, unstable in the light and under load. in presence to-t and alkalis. With p-rum SbCl 3 in CHCl 3 give a characteristic blue color (l max 590 nm).

B-Carotene - dark ruby; in nature is distributed in the form of naib. stable mpans isomer for all double bonds. In solutions under the action of light, with heat. or the addition of iodine partially isomerizes into cis-isomers. When exposed to O 2 or heated in the presence. air b-carotene is gradually oxidized and discolored; oxidation products are decomp. epoxides (eg 5,6-epoxy- and 5,8-epoxy-b-carotenes) and b-ionone derivatives. Hydrogenation in the presence. catalyst leads to partial or complete reduction of double bonds. b-Carotene m. b. isolated by extraction of dry carrots, alfalfa, buckwheat, palm oil, etc. grows. materials. In the prom. scale it receive microbiol. by means of heterotallic. flour fungus Blakeslea trispora, using waste products of starch and syrup production or flour milling (corn, soy flour), as well as synthetically from vitamin A derivatives according to the scheme:


a-Carotene - red crystals; contained in the same plants as b-carotene, but in a much smaller amount (up to 25% of the content of b-carotene). When loading with Na ethoxide partially converted. to b-carotene; optically active ([a] D +315°). Lycopene - red-violet crystals; coloring in-in tomatoes. It is also found in fruits. plant genera; m. b. isolated from tomatoes or obtained synthetically. way. C 40 -Xanthophylls contain one or more hydroxyl, alkoxy, epoxy, aldehyde or ketone groups in the isoprenoid chain. In nature, lutein (Ie), violoxanthin (Ig), neoxanthin (II), fucoxanthin (III), cryptoxanthin (Ih), cantoxanthin (I, R = R" = g), astaxanthin (I, R = R" = h) and etc.


In the homo group - K. combined nature. pigments containing more than 40 C atoms in a molecule. K. with 45, 50 and 56 C atoms are distinguished. Apo-C. Comm. with a shortened polyene chain (37 or less C atoms). Nor-K. include Comm., in which the polyene chain is preserved, but one or several are missing. carbon fragments; contain 39 or less C atoms, for example, bixin (I; R \u003d COOH, R "\u003d COOCH 3). In nature, K. are found both in the free state and in the form of glycosides, carotene proteins or esters formed from one or more molecules of fatty to-t. For the first time, K. were isolated from pepper pods, later from yellow turnips and carrots Daucus carota, from where they got their name. Among plants K. in Naib. Quantities are found in apricots (50-100 µg/g), carrots (80-120 µg/g), parsley leaves (100 µg/g). Qualitatively and quantitatively, K. is determined by the intensity of the maximum absorption of light in the visible region, as well as using chromatography. In the body of animals K. are not synthesized, but come with food. To., having in its composition at least one ring A (see f-lu I), are the precursors of vitamin A. Converting. in the body of these K., containing 40 C atoms, in A with 20 atoms, it is carried out by splitting the K. molecule in the center. double bond or stepwise cleavage, starting from the end of the molecule.

Naib. A-vitamin activity has b-carotene (conditionally it is taken equal to 100%), a-carotene 53%, g-carotene 48%, cryptoxanthin 40%. K. participate in photosynthesis, oxygen transport through cell membranes, protect green plants from the action of light; in animals they stimulate the activity of the gonads, in humans they increase the immune status, protect against photodermatosis, as vitamin A precursors play an important role in the mechanism of vision; natural . To. use as prom. food dyes, components of vitamin animal feed, in honey. practice - for the treatment of affected skin. When eating large quantities of K. hypervitaminosis is not observed. Lit.: Britton G., Biochemistry of natural pigments, trans. With. English, M., 1986; Kretovich VL, Biochemistry of plants. 2nd ed. M., 1986; Goodwin T., Mercer E., Introduction to plant biochemistry, trans. from English, vol. 1-2, M., 1986; Carotenoids, ed. by O. Isler, Basel Stuttg., 1971; Foppen F., "Chromatographic Reviews", 1971, v. 14, p. 133-298. L. A. Vakulova. G. I. Samokhvalov.

Chemical encyclopedia. - M.: Soviet Encyclopedia. Ed. I. L. Knunyants. 1988 .

See what "CAROTENOIDS" are in other dictionaries:

The yellow, orange or red pigments synthesized by hl. arr. bacteria, fungi and higher plants; polyunsaturated hydrocarbons of the terpene series. Animals usually do not form K. (there is information about the synthesis of K. by marine organisms, for example, some ... ... Biological encyclopedic dictionary

CAROTENOIDS- CAROTENOIDS, a group designation of a number of yellow, orange or red pigments, characterized by the ability to dissolve in the same solvents as fats, and making up the main part of the so-called lipochromes. Widespread in... Big Medical Encyclopedia

- (from Latin carota carrot and Greek eidos species) a group of natural yellow or orange pigments. By chemical nature, isoprenoids; unsaturated hydrocarbons (carotenes) or their oxidized derivatives (xanthophylls). Synthesized by some ... ... Big Encyclopedic Dictionary

CAROTENOIDS, a group of fat-soluble plant pigments, yellow to red. They are also found in some animal fats. They are isomers of carotene, a pigment that is converted in the liver into vitamin A, which is necessary for ... ... Scientific and technical encyclopedic dictionary

Pigments of aliphatic or acyclic structure, consisting of isoprene residues, usually yellow or orange. The most numerous and widespread group of microbial pigments. Functions of K. - a) protection of cells from ... ... Dictionary of microbiology

Carotene, lycopene and other carotenoids give color to most orange vegetables and fruits. Carotenoids are tetraterpenes and tetraterpenoids, which are formally derivatives & ...

- (from Latin carota carrot and Greek éidos view), a group of natural yellow or orange pigments. By chemical nature, isoprenoids; unsaturated hydrocarbons (carotenes) or their oxidized derivatives (xanthophylls). Synthesized by some ... ... encyclopedic Dictionary

- (syn. lipochromes obsolete) biologically active fat-soluble yellow, orange or red pigments synthesized by bacteria, fungi and higher plants; some K. are precursors of retinol (vitamin A) ... Big Medical Dictionary

Yellow, orange or red pigments (cyclic or acyclic isoprenoids) synthesized by bacteria, fungi and higher plants. Animals usually do not form K., but use them for the synthesis of vitamin A. K. are widely treated ... ... Great Soviet Encyclopedia

- (from Latin carota carrot and Greek eidos view), a group of natural pigments of yellow or orange color. According to chem. the nature of isoprenoids; unsaturated hydrocarbons (carotenes) or their oxidized derivatives (xanthophylls). Synthesized by some ... ... Natural science. encyclopedic Dictionary

In a review article by V. G. Ladygin and G. N. Shirshikova, modern ideas about the functions of carotenoids - yellow, red and orange pigments - in plants are presented. Carotenoids play a very important role in the operation of the molecular machinery of photosynthesis. They perform three main functions: photoprotective (protecting chlorophyll and other vulnerable components of photosystems from light "overexcitation"), light harvesting (which allows plants to use the energy of light in the blue region of the spectrum - a task that chlorophyll cannot cope without the help of carotenoids) and structural ( serve as necessary structural elements, "bricks" of photosystems).

Carotenoids are a widespread class of pigments found in bacteria, unicellular eukaryotes, fungi, plants, and animals. Unlike a number of other pigments, such as heme (coloring the blood and muscles of mammals red) or chlorophyll (responsible for the green color of plants), carotenoid molecules do not contain metals. They consist only of carbon, hydrogen and oxygen, and their ability to "work" with light quanta is determined by a system of conjugated double bonds between carbon atoms arranged in a chain. Double bonds are called conjugated, separated by one single bond.

Carotenoids absorb light with a wavelength of 280–550 nm (these are the green, blue, violet, and ultraviolet regions of the spectrum). The more conjugated double bonds in a molecule, the longer the wavelength of absorbed light. Accordingly, the color of the pigment also changes. Carotenoids with 3–5 conjugated double bonds are colorless and absorb light in the ultraviolet region. Seven-linked zeta-carotene is yellow, nine-linked neurosporin is orange, and 11-linked lycopene is orange-red.

The functions of carotenoids in wildlife are not limited to working with light, sometimes they play an important role in metabolism (remember, for example, vitamin A is a derivative of beta-carotene). And yet their main functions (whether in the organs of vision of animals or in chloroplasts - the organelles of plant photosynthesis) are inextricably linked with light. The article by Ladygin and Shirshikova discusses the role of carotenoids in chloroplasts, plant cell organelles that originate from symbiotic cyanobacteria. The main function of chloroplasts is photosynthesis, that is, the production of organic matter from carbon dioxide due to the energy of sunlight. Chloroplast membranes contain protein-pigment complexes - photosystems I and II, which include a variety of proteins, as well as pigments - chlorophylls and carotenoids.

Chlorophyll, the main photosynthetic pigment, is itself capable of absorbing and using light only in the red region of the spectrum (650–710 nm). Carotenoids absorb blue-green light and transfer its energy to chlorophylls. This function of carotenoids is light-harvesting- is especially important for algae, since blue-green light penetrates much deeper into the water column than red.

The second function of carotenoids in chloroplasts is light-protective. They protect photosystems from light "overloads" that can lead to overexcitation and malfunction of photosystems. Carotenoids serve as a kind of "emergency valve" that allows you to dump excess energy, convert it into heat. Carotenoids do this in a number of different ways: simply by "filtering" the incoming light, by taking on excess light energy, or by de-energizing overexcited chlorophyll. Carotenoids can also “extinguish” reactive oxygen species, that is, they serve as antioxidants.

One of the ways that carotenoids "dump" excess energy in excess light is through cyclic chemical reactions, during which one carotenoid is converted into another. The most common of these reactions is called the violaxanthin cycle. In strong light, the carotenoid violaxanthin is converted to zeaxanthin, and oxygen is released. When light is reduced, zeaxanthin is converted back to violaxanthin, while oxygen is consumed. Both reactions - both direct and reverse - are catalyzed by enzymes whose genes are located in the chromosome of the chloroplast, and not in the central (nuclear) genome of the plant cell.

The third function of carotenoids is structural. Carotenoids are essential structural components of the photosynthetic membranes of chloroplasts. It has been experimentally shown that photosystems become unstable without carotenoids. Carotenoid molecules occupy strictly defined positions in photosystems, and without them, the whole structure simply falls apart.

The authors note that in recent years a lot of new things have become known about carotenoids, but a number of details remain to be clarified. In particular, the evolutionary origin of carotenoids, as well as biochemical and photochemical reactions with their participation, is not yet fully understood. It is not clear to what extent carotenoids can be used in phylogenetics, that is, to reconstruct the evolutionary development of organisms. In many old works, sets of carotenoids characteristic of one or another group of organisms were used as an important taxonomic feature. It is not entirely clear how reliable such signs are, especially considering that the same carotenoids can be found, for example, in plant chloroplasts and in the eyes of mammals.

Encyclopedia "Biology"

Carotenoids

Natural yellow, orange or red pigments synthesized by bacteria, fungi and green plants. They are divided into carotenes and xanthophylls. Carotenes by chemical nature are unsaturated hydrocarbons, the molecules of which are built from 40 carbon atoms. Spinach leaves, carrot roots, rose hips are rich in carotenes. Animals usually do not synthesize carotenes and get them with food, accumulating in adipose tissue, egg yolk, milk, etc. Vitamin A is formed from carotene (provitamin A) in the animal body. Xanthophylls are oxidized derivatives of carotenes (alcohols, aldehydes, etc.). ). Contained in various organs of plants and in the cells of many microorganisms. Carotenoids serve as additional pigments during photosynthesis, participate in photo-dependent reactions of plants (for example, in tropisms), color (together with other pigments) the autumn foliage of plants.

encyclopedic Dictionary

Carotenoids

(from Latin carota - carrot and Greek eidos - view), a group of natural pigments of yellow or orange color. By chemical nature - isoprenoids; unsaturated hydrocarbons (carotenes) or their oxidized derivatives (xanthophylls). They are synthesized by some microorganisms and all plants in whose cells they participate in photosynthesis and processes associated with the absorption of light (phototaxis, phototropism, etc.). They determine the color of fruits, autumn foliage, colonies of a number of microbes. In the body of animals and humans, vitamin A is formed from carotenes that come with food.

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25.11.2018

Natural dyes that give leaves, flowers, fruits, roots and other parts of plants a color (yellow, orange, red, brown) form a groupcarotenoids , water-insoluble biologically active substances that are synthesized by all types of plants, as well as some microorganisms.

carotenoids along withchlorophyll , providing plants with a green color, are two groupsphotosynthetic pigments and perform the functions of absorbing light with subsequent conversion of solar energy into chemical energy. In addition, carotenoids play a protective role, protecting chlorophyll from excessive exposure to solar energy and from oxidation by oxygen released during photosynthesis. They also provide the structure of the photosystem, occupying a strictly defined position in photosynthetic membranes.

Despite the similarity of their role in the life of plants, chlorophylls and carotenoids have a number of differences. So, chlorophylls absorb mainly light waves of the red, infrared (wavelength 650 - 710 nm), blue and ultraviolet (wavelength 400 - 500 nm) parts of the spectrum, and carotenoids - mainly green, blue, violet, ultraviolet region (length waves 280 - 550 nm). In addition, they have a different molecular structure; carotenoids, unlike chlorophyll, do not contain metals.

Carotenoids, in turn, are represented by two types of fat-soluble polyunsaturated hydrocarbon compounds of the terpene series:carotenes And xanthophylls . Xanthophylls differ from carotenes in that, in addition to carbon and hydrogen, they also contain oxygen atoms.

To date, about 650 different representatives of carotenoids have been studied. Among them are the most common and best known orange pigment. carotene, giving a yellow-orange color to the fruits of fruits and vegetables, as well as other parts of plants (leaves, roots, etc.), and a red pigment lycopene(tomato fruits, watermelon pulp, fruits, berries), which is in essence its isomer. You can also consider carotenes as derivatives of lycopene.

The first carotenoid pigment known to us today ascarotene(lat. carota ), was obtained from the roots of carrots and yellow turnips in 1831 by the German scientist Ferdinand Wackenroder. Much later, the German chemist Richard Wilstetter proposed an empirical formula for carotene C 40 N 56 . And only in 1930, almost a century after the official discovery of carotene, the Swiss chemist Paul Carrer finally confirmed its structural formula, for which the scientist was awarded the Nobel Prize (1937).

Studies have shown that carotene can exist in four forms:α -carotene, β -carotene, γ -carotene and δ -carotene, of which the first three forms areprovitamin A . Once in the human (animal) body, they are converted into vital substancesretinoids(A 1, A 2 , retinoic acid, etc.), which have antioxidant properties (protection of cells from the damaging effects of light energy). β-carotene is the most effective in its action, since it is converted into two molecules of retinol, while the rest (α- and γ-carotene) can form only one.

Opening vitamin A happened in 1913. Its importance for the life of bioorganisms can hardly be overestimated. As a structural component of cell membranes, it has a beneficial effect on growth and development, and is part of the main visual pigment.rhodopsin provides antioxidant protection. The lack of this vitamin in the diet significantly reduces immunity, slows down growth processes, and negatively affects visual functions.