**3. Antioxidants**

*Antioxidants*

**264**

*\**

**Table 1.**

**Figure 1.**

been suggested as retarding the process of cancerous cells taking over a tissue. In an experimental animal model, DHA act inhibiting transcription factor activator protein 1 (AP-1), which has been implicated in the development of cancer [12]. DHA could decrement the risk of neuropsychiatric disorders and could be attribute to their effect on neurotransmitter receptor and G-proteins via effects on the biophysical properties of cell membranes and secondary messengers, and on protein kinases [11, 13, 14]. The consumption of DHA can positively influence to avoid the deterioration caused by Alzheimer's (AD), associated with the production of amyloid beta

**Names Abbreviations**

acid cervonic acid

5,8,11,14,17-eicosapentaenoic

alpha-linolenic acid 18:3<sup>∆</sup>

*Function of omega-3 fatty acid in regulating health markers and omega-3 and omega-6 fatty acid synthesis [7].*

acid 22:5∆

acid 20:5∆

*IUPAC, International Union of Pure and Applied Chemistry. Trivial names, chemical names and abbreviations for the omega-3 fatty acids. Categorize according to their chain length of the polyunsaturated fatty acids (PUFAs) [7].*

**reference**

22:6∆

**Omegareference**

18:3 (ω-3)

22:6 (ω-3)

22:5 (ω-3)

20:5 (ω-3)

9 12 15 18:3n-3

4 8 12 15 19 22:6n-3

7 10 13 16 19 22:5n-3

5 8 11 14 17 20:5n-3

**Other**

ALA α-LA LNA α-LNA

DHA

DPA

**Trivial IUPAC\* Carboxyl-**

Linolenic acid 9,12,15-octadecenoic acid

Docosahexaenoic acid 4,8,12,15,19-docosahexaenoic

Docosapentaenoic acid 7,10,13,16,19-docosapentaenoic

Eicosapentaenoic acid Icosapentaenoic acid Timnodonic acid

*Nomenclature of omega-3 fatty acids.*

Antioxidants include vitamins A, C, and E and selenium.

#### **3.1 Vitamin A**

Carotene is a pigment that animals can turn into vitamin A in their body. C The intestine is the organ that is responsible for transforming carotene into vitamin A for storage in the liver and is rarely stored in fat tissue. Its common form is found as beta-carotene. Due to its chemical structure, it is part of the terpenes, formed by isoprene units (40 carbon atoms). The biosynthesis of these compounds is initially from isopentenyl pyrophosphate.

Beta-carotene was the first purified carotene (*Daucus carota*). Vitamin A is the active form of retinol. Milk and carrots, green vegetables, and some fruits are dietary sources of vitamin A. Isomerization reactions affect the vitamin A content.

Among its functions it is said that it protects the skin from the ultraviolet rays derived from the sun; it also keeps the immune system in optimal conditions, as well as the cardiac system, and is used as an antioxidant.

It is known that the oxidation process of low-density lipoprotein (LDL) decreases the risk of manifesting coronary diseases and arteriosclerosis.

With regard to cancer, it is said that vitamin A allows good cellular functioning by decreasing the development of cancer cells. The intake of this vitamin prevents colon, breast, lung, and oral cavity cancers.

Consumption of vitamin A allows the brain to function in good condition because it has been proven to delay cognitive aging and decrease the oxidative stress derived from the production of free radicals that can generate cell damage generating dementia.

With respect to respiratory diseases, the intake of carotenoids reduces the manifestation of respiratory disorders such as pulmonary emphysema, bronchitis, and asthma to keep the lungs in good condition.

These compounds prevent macular degeneration or loss of sight in adults. Among other things, it prevents skin aging due to its antioxidant properties, since it diminishes the effect of the ultraviolet light generated by the sun's rays and by environmental contamination.

One of the disadvantages due to the excessive use of this vitamin lies in the malformation of the fetus in pregnant women by high doses of carotene continuously.

The reactions that are carried out in the organism are oxidation, reduction, and esterification that give rise to different metabolic processes [16].

#### *3.1.1 Oxidation*

Retinol is the main form of vitamin A; it is a derivative of alcohols. In the eyes, vitamin A plays a fundamental role because it is part of the visual purple of the retina, and if the amount of vitamin A decreases, the ability to see is reduced.

**Figure 2.**

*Synthesis of retinal from beta carotene.*

Beta-carotene is denatured in the walls of the intestinal mucosa where it interacts with the enzyme β-carotene desoxygenase to produce retinal (see **Figure 2**) [16].

#### *3.1.2 Reduction reaction*

The reduction reaction that vitamin A presents involves the passage from retinal to retinol in the presence of the enzyme retinaldehyde reductase in the intestine. The chemical reaction includes the reduction of an aldehyde by accepting hydrogen atoms to produce an alcohol known as retinol.

#### *3.1.3 Esterification reaction*

Retinoids are found in nature in the form of retinol (alcohol) and retinal (aldehyde). The three active forms of vitamin A in the body are retinol, the compound retinal, and retinoic acid. The compound retinal is metabolized in the body, producing retinoic acid and, by esterification reactions, retinol palmitate is produced which is part of the storage in the body.

The digestion of vitamin A is carried out as the degradation of fatty acids, that is, the retinol esters are hydrolyzed by the pancreatic lipase enzymes when they bind to the bile salts forming micelles where the free retinol is absorbed in the intestine specifically in the duodenum and jejunum. The absorption of retinoids is 80–90% and that of carotenoids is 30–40%.

In enterocytes or epithelial cells of the intestine, carotenoids and beta-carotene are attached to the chylomicrons and transported to the liver where they are stored as retinol palmitate. In hepatic cells, retinol binds to the retinol transporter protein (RBP) forming a conjugate by binding to prealbumin in order to travel over the bloodstream where it is transferred to other tissues. On the other hand, carotenoids travel to the bloodstream as part of very-low-density lipoproteins (VLDL) and are stored in adipose tissue.

In dietary supplements vitamin A reduces cancer risk [17].

#### **3.2 Vitamin C**

In 1920, Albert Szent-Györgyi, un bioquímico húngaro, identificó la vitamina C. Después, fue llamado ácido hexurónico por un médico llamado Joseph Svibely, Szent-Györgyi. Más tarde fue nombrado ácido ascórbico por Szent-Györgyi y Norman Haworth, un científico que también estudió la vitamina C [18]. Fue conocido desde su descubrimiento como factor de escorbuto. La vitamina C es un compuesto soluble en agua [19].

**267**

*Importance of the Nutrition with Antioxidants in the Treatment of Cancer and Others Damages*

It is known as ascorbic acid; its chemical name is (R)-3,4,-dihydroxy-5-((S)-1,2 dihydroxyethyl) furan-2(%H)-one. In its oxidized form, it is known as dehydro-

As part of its functions, this compound is considered necessary for the organism since it participates in the growth and repair of tissues in the human body. It is important for the function of the skin, tendons, ligaments, and blood vessels. It is also important to heal wounds and tissues. It also participates in the repair and maintenance of the cartilage, bones, and teeth. Finally, it is important in the iron

It presents oxidation and reduction reactions in the organism, since it gives

Vitamin C is excreted in the small intestine (duodenum) and is passed into the bloodstream through a process of active transport of sodium ions. The process is saturable and dose-dependent. At high concentrations a part of the ascorbic acid is

Its functions depend on the redox processes that is manifested in the interaction with other molecules [19]. Vitamin C functions as a cofactor in various hydroxylation and amination reactions by transferring electrons to enzyme complexes that produce reducing equivalents that facilitate the conversion of proline and lysine, which are amino acids that are part of procollagen in the form of hydroxyproline and hydroxylysine during synthesis of collagen. It also participates in the oxidation of the lysine side chains to form hydroxytrimethylisin in the synthesis of carnitine and in the conversion of folic acid into folinic acid. It is also an essential compound in the oxidation of amino acids such as phenylalanine and tyrosine and is important in the metabolism of tryptophan, and participates in the synthesis of noradrenaline [20]. It is considered an antioxidant agent because of its ability to capture free radicals

Vitamin C prevents the oxidation of low-density lipoproteins (LDL) facilitating the absorption of iron [22]. In foods rich in vitamin C such as broccoli and cauliflower, it was shown that it has a correlation of phytochemicals (phenol, flavonoid, and glucosinolate) [23]. Another study highlighted the antioxidant capacity of

The physiological importance of vitamin C is its role as a cofactor and its partici-

Vitamin C protects cell membranes, DNA [25], cellulose proteins and lipids against the oxidative effects of free radicals (ROS) [26, 27] and reactive oxygen species. At the immunological level, it stimulates phagocytosis and the formation of

Adverse reactions to the consumption of this vitamin are rare, but care should be taken when dosing pregnant women. It can cause nausea, vomiting, acidity, abdominal cramps, fatigue, headache, insomnia, and drowsiness. Inappropriate

In heroin addicts who present with oxidative stress, vitamin C levels [29, 30] can damage their health. Foods rich in potassium tend to be high in vitamin C; there-

Vitamin E is a substance with liposoluble characteristics and has been reported to have antioxidant properties. It is chemically presented with eight isoforms of vitamin E: four tocopherols (α, β, and δ) and four tocotrienols (α, β, and δ). It is found in foods such as wheat germ and sunflower, safflower, corn, and soybean oils.

*DOI: http://dx.doi.org/10.5772/intechopen.85469*

hydronium ions to form L-dehydroascorbic acid.

<sup>−</sup>, and hypochlorous acid [21].

diffused by a simple diffusion process.

ascorbic acid (C6H8O6).

absorption process.

such as H2O2, O2

antibodies.

vitamin C in fruits [24].

**3.3 Alpha-tocopherol**

pation in enzyme reduction reactions [22].

consumption of vitamin C can cause arthritis [28].

fore, a decrease in potassium causes a decrease in vitamin C [31–34].

*Importance of the Nutrition with Antioxidants in the Treatment of Cancer and Others Damages DOI: http://dx.doi.org/10.5772/intechopen.85469*

It is known as ascorbic acid; its chemical name is (R)-3,4,-dihydroxy-5-((S)-1,2 dihydroxyethyl) furan-2(%H)-one. In its oxidized form, it is known as dehydroascorbic acid (C6H8O6).

As part of its functions, this compound is considered necessary for the organism since it participates in the growth and repair of tissues in the human body. It is important for the function of the skin, tendons, ligaments, and blood vessels. It is also important to heal wounds and tissues. It also participates in the repair and maintenance of the cartilage, bones, and teeth. Finally, it is important in the iron absorption process.

It presents oxidation and reduction reactions in the organism, since it gives hydronium ions to form L-dehydroascorbic acid.

Vitamin C is excreted in the small intestine (duodenum) and is passed into the bloodstream through a process of active transport of sodium ions. The process is saturable and dose-dependent. At high concentrations a part of the ascorbic acid is diffused by a simple diffusion process.

Its functions depend on the redox processes that is manifested in the interaction with other molecules [19]. Vitamin C functions as a cofactor in various hydroxylation and amination reactions by transferring electrons to enzyme complexes that produce reducing equivalents that facilitate the conversion of proline and lysine, which are amino acids that are part of procollagen in the form of hydroxyproline and hydroxylysine during synthesis of collagen. It also participates in the oxidation of the lysine side chains to form hydroxytrimethylisin in the synthesis of carnitine and in the conversion of folic acid into folinic acid. It is also an essential compound in the oxidation of amino acids such as phenylalanine and tyrosine and is important in the metabolism of tryptophan, and participates in the synthesis of noradrenaline [20].

It is considered an antioxidant agent because of its ability to capture free radicals such as H2O2, O2 <sup>−</sup>, and hypochlorous acid [21].

Vitamin C prevents the oxidation of low-density lipoproteins (LDL) facilitating the absorption of iron [22]. In foods rich in vitamin C such as broccoli and cauliflower, it was shown that it has a correlation of phytochemicals (phenol, flavonoid, and glucosinolate) [23]. Another study highlighted the antioxidant capacity of vitamin C in fruits [24].

The physiological importance of vitamin C is its role as a cofactor and its participation in enzyme reduction reactions [22].

Vitamin C protects cell membranes, DNA [25], cellulose proteins and lipids against the oxidative effects of free radicals (ROS) [26, 27] and reactive oxygen species. At the immunological level, it stimulates phagocytosis and the formation of antibodies.

Adverse reactions to the consumption of this vitamin are rare, but care should be taken when dosing pregnant women. It can cause nausea, vomiting, acidity, abdominal cramps, fatigue, headache, insomnia, and drowsiness. Inappropriate consumption of vitamin C can cause arthritis [28].

In heroin addicts who present with oxidative stress, vitamin C levels [29, 30] can damage their health. Foods rich in potassium tend to be high in vitamin C; therefore, a decrease in potassium causes a decrease in vitamin C [31–34].

#### **3.3 Alpha-tocopherol**

Vitamin E is a substance with liposoluble characteristics and has been reported to have antioxidant properties. It is chemically presented with eight isoforms of vitamin E: four tocopherols (α, β, and δ) and four tocotrienols (α, β, and δ). It is found in foods such as wheat germ and sunflower, safflower, corn, and soybean oils.

*Antioxidants*

**Figure 2.**

*3.1.2 Reduction reaction*

*Synthesis of retinal from beta carotene.*

*3.1.3 Esterification reaction*

stored in adipose tissue.

compuesto soluble en agua [19].

**3.2 Vitamin C**

atoms to produce an alcohol known as retinol.

which is part of the storage in the body.

80–90% and that of carotenoids is 30–40%.

Beta-carotene is denatured in the walls of the intestinal mucosa where it interacts with the enzyme β-carotene desoxygenase to produce retinal (see **Figure 2**) [16].

The reduction reaction that vitamin A presents involves the passage from retinal to retinol in the presence of the enzyme retinaldehyde reductase in the intestine. The chemical reaction includes the reduction of an aldehyde by accepting hydrogen

Retinoids are found in nature in the form of retinol (alcohol) and retinal (aldehyde). The three active forms of vitamin A in the body are retinol, the compound retinal, and retinoic acid. The compound retinal is metabolized in the body, producing retinoic acid and, by esterification reactions, retinol palmitate is produced

The digestion of vitamin A is carried out as the degradation of fatty acids, that is, the retinol esters are hydrolyzed by the pancreatic lipase enzymes when they bind to the bile salts forming micelles where the free retinol is absorbed in the intestine specifically in the duodenum and jejunum. The absorption of retinoids is

In enterocytes or epithelial cells of the intestine, carotenoids and beta-carotene are attached to the chylomicrons and transported to the liver where they are stored as retinol palmitate. In hepatic cells, retinol binds to the retinol transporter protein (RBP) forming a conjugate by binding to prealbumin in order to travel over the bloodstream where it is transferred to other tissues. On the other hand, carotenoids travel to the bloodstream as part of very-low-density lipoproteins (VLDL) and are

In 1920, Albert Szent-Györgyi, un bioquímico húngaro, identificó la vitamina C. Después, fue llamado ácido hexurónico por un médico llamado Joseph Svibely, Szent-Györgyi. Más tarde fue nombrado ácido ascórbico por Szent-Györgyi y Norman Haworth, un científico que también estudió la vitamina C [18]. Fue conocido desde su descubrimiento como factor de escorbuto. La vitamina C es un

In dietary supplements vitamin A reduces cancer risk [17].

**266**

It is absorbed in the small intestine and is passed into the bloodstream by transporting plasma lipoproteins. The serum vitamin E levels reported are from 11.6 to 46.4 μmol/L.

Vitamin E group includes all of the tocol and tocotrienol derivatives which qualitatively exhibit the biological activity of d-alpha-tocopherol. There are eight natural forms of vitamin E and they are divided into 2 fundamental groups: the 4 tocopherols (TF) and the 4 tocotrienols (TT) that differ in the saturation of the side chain; the tocopherols have a saturated chain and the tocotrienols an unsaturated with 3 double bonds. They are classified into alpha, beta, gamma and delta classes and derivatives of tocopherol and tocotrienol, which are synthesized by plants from homogentisic acid. Alpha and gamma-tocopherols are the two main forms of vitamin E. Vitamin E is known as alpha-tocopherol because it is the most abundant isoform in nature. It is absorbed in greater proportion in the gastrointestinal tract and is responsible for the activity in many metabolic processes.

The beneficial properties of alpha-tocopherol are manifested when the hydronium H+ phenolic ion is transferred to a radical derived from polyunsaturated fatty acids.

It is the first line of defense against DNA oxidative damage and the peroxidation of polyunsaturated fatty acids in cell membranes.

It is found in many foods of vegetable origin such as nuts, hazelnuts, almonds, and pistachios and also in different food supplements. It has been proven that adverse reactions are minimal. Therefore, it is an excellent preventive compound of diseases and is part of the diet of man [35].

Currently it has been reported that tocopherols inhibit platelet aggregation by inhibiting protein kinase C (PKC) [36, 37] and increase the activity of nitric oxide synthase enzymes, the catalytic enzyme N-arginine and L-citrulline [38].

Alpha-tocopherol is used in inflammatory processes, in its inhibition of platelet aggregation, in the activity of the immune system, and in the reduction of cardiovascular complications (gamma-tocopherol) [39, 40].

In Alzheimer's disease (AD), amyloid beta protein is a substance involved in the cytotoxic processes due to peroxidation and the production of free radicals that produces cell death in the brain producing the symptoms of this disease. This is why vitamin E can act by blocking peroxide production and decreasing cytotoxic effects.

Alpha-tocopherol as an anti-inflammatory can decrease the discomfort caused in patients positive for the human immunodeficiency virus (HIV). Doses of 400 IU of alpha-tocopherol restore cutaneous hypersensitivity and interleukin-2 production, as well as increased proliferation of helper T cells (CD4 T cells) [41–45].

In the immune system, alpha-tocopherol increases the conditions of biological immunity in humans, the humoral and cellular immune response, and the phagocytosis process [46–49].

It is said that the antioxidant effect of vitamin E in combination with alpha-lipoic acid (AAL) enhances its antioxidant effect in cardiovascular and brain diseases [50].

#### **3.4 Selenium**

The selenium atom can be presented in different allotropic forms, in its vitreous and black form. When reduced it appears red. It has various uses, for example, for the treatment of seborrheic arthritis.

This element is found in foods like bread, cereals, fish, meat, lentils, potato peel, and eggs. It is found in conjugated amino acid molecules such as selenocysteine and selenomethionine, glutathione peroxidase enzymes (GSHPx), and thioredoxin reductase that have selenium in their chemical structure.

**269**

**Table 2.**

*Importance of the Nutrition with Antioxidants in the Treatment of Cancer and Others Damages*

Is critical for cellular function and is not an essential nutrient because humans can synthesize it from other compounds. It is an acidic amino acids, or negatively charged at physiological pH, because it has a second carboxyl group in its secondary

The DHA is found at high concentrations in the phospholipids of neural cell membranes, where it serves several physiologic functions, including the regulation of membrane fluidity, the release of neurotransmitters, genetic expression, myelination, and cellular differentiation, and

reduces certain enzymes by providing them with

membrane repair by preventing the formation of oxidized phospholipids that theoretically might interfere with the membrane fusion events.

functions in the body as the role in vision.

increase in glutathione peroxidase (GSHPx)

activity.

Contributes to trophism, since the small intestine is the body's main glutamine consumer, is the precursor of glutathione, a key molecule in the antioxidant chain, modulates the inflammatory response in different cells of the immune system and regulates cytokine production; protects cells from diverse insults, including heat shock proteins and apoptosis.

The consumption of DHA could prevent the deterioration caused by

Vitamin C decreases more quickly with increased oxidative stress, therefore, vitamin C is used to control oxidative stress.

Regulation of platelet, aggregation and protein kinase C activation, in disease prevention, cardiovascular diseases, cancer, cataracts, Alzheimer´s disease, human immunodeficiency virus and acquired immunodeficiency syndrome and the immunity.

Decrement the risk of breast or lung cancer.

Se, may inhibit lipid peroxidation in higher plants through GSH-Px and no enzymatic reactions.

Alzheimer's.

chain.

growth.

electrons.

Vitamin C Relation as a cofactor and

Vitamin E Vitamin E promotes

β-carotene Vitamin A has several

Selenium Associated with an

*Description of some antioxidants, chemist, structure, function and treatment.*

**Antioxidant Chemist structure Function Treatment**

*DOI: http://dx.doi.org/10.5772/intechopen.85469*

Glutamic ácid [C5H9NO4] or glutamine

Docohexanoic acid [C22H32O2]

As an antioxidant it participates in the neutralization of free radicals in the process of the production of peroxides; it also induces apoptosis and is an agent *Importance of the Nutrition with Antioxidants in the Treatment of Cancer and Others Damages DOI: http://dx.doi.org/10.5772/intechopen.85469*


#### **Table 2.**

*Description of some antioxidants, chemist, structure, function and treatment.*

*Antioxidants*

46.4 μmol/L.

H+

It is absorbed in the small intestine and is passed into the bloodstream by transporting plasma lipoproteins. The serum vitamin E levels reported are from 11.6 to

Vitamin E group includes all of the tocol and tocotrienol derivatives which qualitatively exhibit the biological activity of d-alpha-tocopherol. There are eight natural forms of vitamin E and they are divided into 2 fundamental groups: the 4 tocopherols (TF) and the 4 tocotrienols (TT) that differ in the saturation of the side chain; the tocopherols have a saturated chain and the tocotrienols an unsaturated with 3 double bonds. They are classified into alpha, beta, gamma and delta classes and derivatives of tocopherol and tocotrienol, which are synthesized by plants from homogentisic acid. Alpha and gamma-tocopherols are the two main forms of vitamin E. Vitamin E is known as alpha-tocopherol because it is the most abundant isoform in nature. It is absorbed in greater proportion in the gastrointestinal tract

The beneficial properties of alpha-tocopherol are manifested when the hydronium

 phenolic ion is transferred to a radical derived from polyunsaturated fatty acids. It is the first line of defense against DNA oxidative damage and the peroxidation

It is found in many foods of vegetable origin such as nuts, hazelnuts, almonds, and pistachios and also in different food supplements. It has been proven that adverse reactions are minimal. Therefore, it is an excellent preventive compound of

Currently it has been reported that tocopherols inhibit platelet aggregation by inhibiting protein kinase C (PKC) [36, 37] and increase the activity of nitric oxide synthase

Alpha-tocopherol is used in inflammatory processes, in its inhibition of platelet aggregation, in the activity of the immune system, and in the reduction of cardio-

In Alzheimer's disease (AD), amyloid beta protein is a substance involved in the cytotoxic processes due to peroxidation and the production of free radicals that produces cell death in the brain producing the symptoms of this disease. This is why vitamin E can act by blocking peroxide production and decreasing cytotoxic effects. Alpha-tocopherol as an anti-inflammatory can decrease the discomfort caused in patients positive for the human immunodeficiency virus (HIV). Doses of 400 IU of alpha-tocopherol restore cutaneous hypersensitivity and interleukin-2 production, as well as increased proliferation of helper T cells (CD4 T cells) [41–45].

In the immune system, alpha-tocopherol increases the conditions of biological immunity in humans, the humoral and cellular immune response, and the phagocy-

It is said that the antioxidant effect of vitamin E in combination with alpha-lipoic acid (AAL) enhances its antioxidant effect in cardiovascular and brain diseases [50].

The selenium atom can be presented in different allotropic forms, in its vitreous and black form. When reduced it appears red. It has various uses, for example, for

This element is found in foods like bread, cereals, fish, meat, lentils, potato peel,

and eggs. It is found in conjugated amino acid molecules such as selenocysteine and selenomethionine, glutathione peroxidase enzymes (GSHPx), and thioredoxin

As an antioxidant it participates in the neutralization of free radicals in the process of the production of peroxides; it also induces apoptosis and is an agent

and is responsible for the activity in many metabolic processes.

enzymes, the catalytic enzyme N-arginine and L-citrulline [38].

vascular complications (gamma-tocopherol) [39, 40].

of polyunsaturated fatty acids in cell membranes.

diseases and is part of the diet of man [35].

**268**

tosis process [46–49].

the treatment of seborrheic arthritis.

reductase that have selenium in their chemical structure.

**3.4 Selenium**

#### *Antioxidants*

that stimulates the immune system and participates in the proper functioning of the thyroid gland. Studies of this element indicate that it can prevent cancer by the chemoprotective action against oxidative stress. It is found in the form of selenite and selenate or as a conjugate derived from amino acids; the latter is beneficial for humans. It can be toxic at high doses causing the disease known as selenosis [51].

It is important in genetic engineering since the UGA termination codon serves as a codon for Se-cysteine and can be decoded by Se-cysteyl-tRNAs in herbs; so, this chemical element has specific biological functions. In **Table 2**, we show some antioxidants.
