Antioxidants: effects on the body and sources

What is free radicals?

Free radicals are the result of the wrong processes that occur inside the body, and the result of human life. Free radicals also appear from an unfavorable environment, in a bad climate, harmful production conditions and temperature fluctuations.

Even though a person leads a healthy lifestyle, he is exposed to free radicals that destroy the structure of body cells and activate the production of the following portions of free radicals. Antioxidants protect cells from damage and oxidation as a result of the action of free radicals. But in order to keep the body healthy, you need enough servings of antioxidants. Namely - products with their content and additives with antioxidants.

Effects of free radicals

Every year, medical scientists add to the list of diseases caused by exposure to free radicals. This is the risk of cancer, heart and vascular disease, eye disease, in particular, cataracts, as well as arthritis and other deformations of bone tissue.

With these diseases, antioxidants are successfully fighting . They help make a person healthier and less exposed to the environment. In addition, studies prove that antioxidants help control weight and stabilize metabolism. That's why a person should consume them in sufficient quantities.

Antioxidant beta-carotene

It's a lot in orange vegetables. It's a pumpkin, carrot, potato. And more beta-carotene is a lot in vegetables and fruits of green color: salads of different kinds (leaf), spinach, cabbage, especially broccoli, mango, melon, apricots, parsley, dill.

The dose of beta-carotene per day: 10 000-25 000 units

Antioxidant vitamin C

It is good for those who want to strengthen their immunity, reduce the risk of stones in the bile and kidneys. Vitamin C is rapidly destroyed during processing, so you need to eat fresh vegetables and fruits with it. Vitamin C is abundant in mountain ash, black currant, oranges, lemons, strawberries, pears, potatoes, bell peppers, spinach, tomatoes.

The dose of vitamin C per day: 1000-2000 mg

Antioxidant vitamin E

Vitamin E is indispensable in the fight against free radicals, the code in humans is hypersensitive to glucose, and in the body - too much of its concentration. Vitamin E helps to reduce it, as well as immunity to insulin. Vitamin E, or tocopherol, is naturally found in almonds, peanuts, walnuts, hazelnuts, asparagus, peas, wheat grains (especially sprouted), oats, corn, cabbage. There is it in vegetable oils.

Vitamin E is important not to use synthesized, but natural. It can be easily distinguished from other types of antioxidants by a mark on the label with the letter d. That is, d-alpha-tocopherol. Non-natural antioxidants are referred to as dl. That is dl-tocopherol. Knowing this, you can benefit your body, not harm.

The dose of vitamin E per day: 400-800 units (natural form of d-alpha-tocopherol)

Selenium antioxidant

The quality of the selenium that enters your body depends on the quality of the products grown with this antioxidant, and also on the soil on which they grew. If the soil is poor in minerals, then selenium in the products that grew on it will be of poor quality. Selenium can be found in fish, poultry, wheat, tomatoes, broccoli,

The content of selenium in plant products depends on the state of the soil on which they were grown, on the mineral content in it. It can be found in broccoli, onions.

Selenium dose per day: 100-200 μg

What antioxidants can effectively lose weight?

There are such kinds of antioxidants that activate the process of metabolism and help to lose weight. They can be bought at a pharmacy and used under the supervision of a doctor.

Antioxidant coenzyme Q10

The composition of this antioxidant is almost the same as that of vitamins. He actively promotes metabolic processes in the body, in particular, oxidative and energetic. The longer we live, the less our body produces and accumulates coenzyme Q10.

Its properties for immunity are priceless - they are even higher than that of vitamin E. Coenzyme Q10 can even help cope with the pain. It stabilizes the pressure, in particular, with hypertension, and also promotes good work of the heart and blood vessels. Coenzyme Q 10 is able to reduce the risk of heart failure.

This antioxidant can be obtained from meat of sardines, salmon, mackerel, perch, and also it is in peanuts, spinach.

To antioxidant Q10 is well absorbed by the body, it is desirable to take it with oil - there it dissolves well and is quickly absorbed. If you use the antioxidant Q10 in oral tablets, you need to carefully study its composition, so as not to fall into the trap of poor-quality products. It is better to buy such drugs that are placed under the tongue - so they are more quickly absorbed by the body. And it is even better to replenish body reserves with natural coenzyme Q10 - the body absorbs and processes it much better.

The effect of basic fatty acids

Essential fatty acids are irreplaceable for our body, because they perform many roles in it. For example, promote the production of hormones, as well as transmitters of hormones - prostaglandins. Essential fatty acids are also needed for the production of hormones such as testosterone, corticosteroids, in particular, cortisol, and also progesterone.

To the brain activity and nerves were normal, basic fatty acids are also needed. They help the cells to protect themselves from damage and recover from them. Fatty acids help synthesize other body products - fats.

Fatty acids - a deficit, unless a person consumes them with food. Because the human body can not produce them.

Omega-3 fatty acids

These acids are especially good when you need to fight excess weight. They stabilize metabolic processes in the body and contribute to a more stable functioning of the internal organs.

Eicosapentaenoic acid (EPA) and alpha-linolenic acid (ALA) are representatives of omega-3 fatty acids. They are best taken from natural products, and not from synthetic additives. These are deep-sea fish mackerel, salmon, sardines, plant oils - olive, corn, walnut, sunflower - they have the largest concentration of fatty acids.

But even despite the natural appearance, many of these supplements can not be used, because they can increase the risk of pain in the muscles and joints due to the increased concentration of eicosanoid substances.

Ratio of substances in fatty acids

Also, make sure that there are no substances in the additives that are treated thermally - such additives destroy the beneficial substances of the preparation. It is more useful for health to use those additives, in the composition of which substances that have passed the process of cleansing from decomposers (cotamins).

It is better to take all the acids that you consume from natural products. They are better absorbed by the body, after their use there are no side effects and much more useful for metabolic processes. Natural supplements do not contribute to weight gain.

The ratio of useful substances in fatty acids is very important so that there will be no malfunctioning of the body. It is especially important for those who do not want to recover, the balance of eicosanoids - substances that can have both bad and good effect on the body.

As a rule, for the best effect you need to use fatty acids omega-3 and omega-6. This will give a better effect if the ratio of these acids is 1-10 mg for omega-3 and 50 - 500 mg of omega-6.

Omega-6 fatty acids

Its representatives are LC (linoleic acid) and GLA (gamma-linolenic acid). These acids help build and repair cell membranes, promote the synthesis of unsaturated fatty acids, help restore cellular energy, control mediators that transmit pain impulses, help strengthen immunity.

Omega-6 fatty acids are abundant in nuts, beans, seeds, vegetable oils, sesame seeds.

Structure and mechanisms of action of antioxidants

There are three types of pharmacological preparations of antioxidants - inhibitors of free radical oxidation, differing in the mechanism of action.

• Oxidation inhibitors interacting directly with free radicals;
• Inhibitors interacting with hydroperoxides and "destroying" them (a similar mechanism was developed using the example of dialkyl sulfides RSR);
• Substances that block free-radical oxidation catalysts, primarily metal ions of variable valence (as well as EDTA, citric acid, cyanide compounds), due to the formation of complexes with metals.

In addition to these three basic types, we can identify the so-called structural antioxidants, the anti-oxidative action of which is due to a change in the structure of the membranes (such antioxidants include androgens, glucocorticoids, progesterone). Antioxidants, apparently, include substances that increase the activity or content of antioxidant enzymes - superoxide dismutase, catalase, glutathione peroxidase (in particular, silymarin). Speaking about antioxidants, it is necessary to mention one more class of substances that enhance the effectiveness of antioxidants; Being synergists of the process, these substances, acting as donators of protons for phenolic antioxidants, contribute to their recovery.

The combination of antioxidants with synergists significantly exceeds the action of one antioxidant. Such synergists, which significantly enhance the inhibitory properties of antioxidants, include, for example, ascorbic and citric acid, as well as a number of other substances. When two antioxidants interact, of which one is strong and the other weak, the latter also acts predominantly as a protonador in accordance with the reaction.

Based on the reaction rates, any inhibitor of peroxide processes can be characterized by two parameters: antioxidant activity and antiradical activity. The latter is determined by the rate at which the inhibitor reacts with free radicals, and the first characterizes the total ability of the inhibitor to inhibit lipid peroxidation, it is determined by the ratio of reaction rates. These indicators are the main ones in characterizing the mechanism of action and activity of an antioxidant, but far from all cases these parameters have been sufficiently studied.

The question of the relationship between the antioxidant properties of a substance and its structure remains open until now. Perhaps, this issue has been most fully developed for flavonoids, the antioxidant effect of which is due to their ability to extinguish OH and O2 radicals. Thus, in the model system, the activity of flavonoids in the plan for "eliminating" hydroxyl radicals increases with the increase in the number of hydroxyl groups in the B ring, and the role of hydroxyl at C3 and the carbonyl group at the C4 position also play an increasing role in the activity. Glycosylation does not alter the ability of flavonoids to extinguish hydroxyl radicals. At the same time, according to other authors, myricetin, on the contrary, increases the rate of formation of lipid peroxides, whereas kaempferol reduces it, and the effect of morine depends on its concentration, while of the three named substances, kempferol is most effective in preventing toxic consequences of peroxidation . Thus, even with respect to flavonoids, there is no final clarity in this matter.

With the example of ascorbic acid derivatives having alkyl substituents at the 2-O position, it has been shown that the presence of a 2-phenolic hydroxy group and a long alkyl chain in the 2-O position is important for the biochemical and pharmacological activity of these substances. The essential role of the long chain is noted for other antioxidants. Synthetic antioxidants phenolic type with shielded hydroxyl and short-chain derivatives of tocopherol exert a damaging effect on the mitochondrial membrane, causing an uncoupling of oxidative phosphorylation, while tocopherol and its long-chain derivatives do not possess such properties. Synthetic antioxidants of phenolic nature, devoid of side hydrocarbon chains, characteristic of natural antioxidants (tocopherols, ubiquinones, naphthoquinones), also cause Ca leakage through biological membranes.

In other words, short-chain antioxidants or antioxidants devoid of side-chain carbon chains tend to have a weaker antioxidant effect and cause side effects (disturbance of Ca homeostasis induction of hemolysis, etc.). However, the available data do not yet allow us to draw a final conclusion about the nature of the relationship between the structure of the substance and its antioxidant properties: the number of compounds possessing antioxidant properties is too large, especially since the antioxidant effect can be the result of not one but a number of mechanisms.

The properties of any substance acting as an antioxidant (in contrast to other effects) are nonspecific, and one antioxidant can be replaced by another natural or synthetic antioxidant. However, a number of problems arise here related to the interaction of natural and synthetic inhibitors of lipid peroxidation, the possibilities of their interchangeability, the principles of replacement.

It is known that the replacement of effective natural antioxidants (primarily a-tocopherol) in the body can be achieved by introducing only such inhibitors that have high antiradical activity. But here there are other problems. Introduction of synthetic inhibitors in the body has a significant effect not only on the processes of lipid peroxidation, but also on the metabolism of natural antioxidants. The effect of natural and synthetic inhibitors can add up, resulting in an increase in the effectiveness of the effect on the processes of lipid peroxidation, but, in addition, the introduction of synthetic antioxidants can affect the synthesis and utilization of natural inhibitors of peroxidation, as well as induce changes in the antioxidant activity of lipids. Thus, synthetic antioxidants can be used in biology and medicine as drugs that affect not only the processes of free radical oxidation, but also the system of natural antioxidants, influencing the changes in antioxidant activity. This possibility of influencing the changes in antioxidant activity is extremely important, as it has been shown that all the investigated pathological states and changes in the processes of cellular metabolism can be divided according to the nature of the changes in antioxidant activity to the processes occurring at an elevated, reduced and stepwise varying level of antioxidant activity. And there is a direct link between the speed of the process, the severity of the disease and the level of antioxidant activity. In this regard, the use of synthetic inhibitors of free radical oxidation is very promising.

Problems of gerontology and antioxidants

Given the participation of free radical mechanisms in the aging process, it was natural to assume the possibility of increasing life expectancy with the help of antioxidants. Such experiments in mice, rats, guinea pigs, Neurospora crassa and Drosophila were carried out, but their results are rather difficult to interpret unambiguously. The contradictory nature of the data obtained can be explained by the inadequacy of the methods for assessing the final results, the incompleteness of work, a superficial approach to assessing the kinetics of free radical processes, and other causes. However, in experiments on fruit flies, a significant increase in life expectancy was observed under the action of thiazolidine carboxylate, and in a number of cases an increase in the average probable but not actual life expectancy was observed. The experiment, conducted with the participation of elderly volunteers, did not yield definite results, in large part because of the inability to ensure the correctness of the conditions of the experiment. However, the fact of an increase in life expectancy in Drosophila, caused by an antioxidant, is encouraging. Perhaps, further work in this area will be more successful. An important evidence in favor of the prospects of this direction is the data on the prolongation of vital activity of the organs under test and the stabilization of metabolism under the action of antioxidants.

Antioxidants in clinical practice 

In recent years, there has been a noticeable interest in free radical oxidation and, as a consequence, for drugs capable of exerting an effect on it. Taking into account the prospects of practical use, antioxidants attract special attention. No less active than the study of already known antioxidant properties of drugs, the search for new compounds that have the ability to inhibit free radical oxidation at different stages of the process.

Among the antioxidants most studied at the present time is primarily vitamin E. This is the only natural lipid-soluble antioxidant that terminates oxidation chains in the blood plasma and membranes of human erythrocytes. The content of vitamin E in plasma is estimated at 5 ~ 10%.

High biological activity of vitamin E and, first of all, its antioxidant properties caused widespread use of this drug in medicine. It is known that vitamin E causes a positive effect with radiation damage, malignant growth, coronary heart disease and myocardial infarction, atherosclerosis, in the treatment of patients with dermatoses (spontaneous panniculitis, nodal erythema), with burns and other pathological conditions.

An important aspect of the use of a-tocopherol and other antioxidants is their use in various stress conditions, when the antioxidant activity is sharply reduced. It is established that vitamin E reduces the intensity of lipid peroxidation increased as a result of stress during immobilization, acoustic and emotional-painful stresses. The drug also prevents violations in the liver during hypokinesia, which causes an increase in free radical oxidation of unsaturated lipid fatty acids, especially in the first 4 to 7 days, that is, during a period of severe stress reaction.

Of the synthetic antioxidants, the most effective is ionol (2,6-di-tert-butyl-4-methylphenol), known in the clinic as dibunol. The anti-radical activity of this drug is lower than that of vitamin E, however, the antioxidant is much higher than that of a-tocopherol (for example, a-tocopherol inhibits the oxidation of methyloleate 6 times, and the oxidation of arachidone is 3 times weaker than that of ionol).

Ionol, like vitamin E, is widely used to prevent disorders caused by various pathological conditions taking place against the background of increased activity of peroxide processes. Like a-tocopherol, ionol is successfully used for the prevention of acute ischemic damage to organs and postischemic disorders. The drug is highly effective in the treatment of cancer, is used for radiation and trophic lesions of the skin and mucous membranes, has been successfully used in the therapy of patients with dermatoses, promotes rapid healing of ulcerative lesions of the stomach and duodenum. Like a-tocopherol, dibunol is highly effective in stress, causing normalization of the level of lipid peroxidation increased as a result of stress. Ionol also possesses some properties of antihypoxants (increases life expectancy in acute hypoxia, accelerates the recovery process after hypoxic disorders), which also seems to be due to the intensification of peroxide processes during hypoxia, especially during the reoxygenation period.

Interesting data were obtained with the use of antioxidants in sports medicine. Thus, the ionol prevents the activation of peroxide oxidation of lipids under the influence of maximum physical exertion, increases the duration of work of athletes at maximum loads, i.e., endurance of the body during physical work, increases the efficiency of the left ventricle of the heart. Along with this, the ionol prevents violations of the higher parts of the central nervous system that occur when the body exerts the greatest physical exertion and is also associated with processes of free radical oxidation. Attempts were made to use in sport practice also vitamin E and vitamins of group K, which also increase physical performance and accelerate recovery processes, but the problems of using antioxidants in sports still require in-depth study.

The antioxidant effect of other drugs has been studied in less detail than the effects of vitamin E and dibunol, and these substances are often viewed as a sort of standard.

Naturally, the closest attention is paid to preparations that are close to vitamin E. So, along with the vitamin E itself, its water-soluble analogues also possess antioxidant properties: trolax C and a-tocopherol polyethylene glycol 1000 succinate (TPGS). Trolox C acts as an effective quencher of free radicals by the same mechanism as vitamin E, and TPGS is even more effective than vitamin E as a protector of SSC-induced lipid peroxidation. As a sufficiently effective antioxidant, a-tocopherol acetate acts: it normalizes the glow of blood serum, increased as a result of the action of pro-oxidants, suppresses lipid peroxidation in the brain, heart, liver and erythrocyte membranes under acoustic stress conditions, is effective in treating patients with dermatoses, regulating the intensity of peroxide processes .

In vitro experiments, antioxidant activity of a number of drugs has been established, the effect of which in vivo can be largely determined by these mechanisms. Thus, the ability of the antiallergic preparation of traniolast to dose-dependently decrease the levels of O2-, H2O2 and OH- in a suspension of human polymorphonuclear leukocytes has been shown. Also, in vitro successfully inhibited Fe2 + / ascorbate-induced peroxidation in liposomes (by ~ 60%) chloropromazine and slightly worse (-20%) - its synthetic derivatives N-benzoyloxymethylchloropromazine and N-pivaloyloxymethyl-chloropromazine. On the other hand, these same compounds embedded in liposomes, when irradiated with ultraviolet light, act as photosensitizing agents and lead to activation of lipid peroxidation. A study of the effect of protoporphyrin IX on peroxidation in rat liver homogenates and subcellular organelles also showed the ability of protoporphyrin to inhibit Fe and ascorbate-dependent lipid peroxidation, however, the preparation did not have the ability to suppress autoxidation in a mixture of unsaturated fatty acids. The study of the mechanism of antioxidant action of protoporphyrin has shown only that it is not related to quenching of radicals, but did not provide enough data to more accurately characterize this mechanism.

By chemiluminescent methods, the ability of adenosine and its chemically stable analogues to inhibit the formation of reactive oxygen radicals in human neutrophils has been established in in vitro experiments.

The study of the effect of oxybenzimidazole and its derivatives of alkyloxybenzimidazole and alkyl ethoxybenzimidazole on the liver microsome membranes and brain synaptosomes upon activation of lipid peroxidation has shown the effectiveness of alkyloxybenzimidazole, more hydrophobic than oxybenzimidazole, and possesses, in contrast to the alkyl ethoxybenzimidazole, an OH group necessary to provide antioxidant activity as an inhibitor of free radicals processes.

The effective quencher of the highly reactive hydroxyl radical is allopurinol, one of the products of the reaction of allopurinol with hydroxyl radical being oxypurinol, its main metabolite, an even more effective hydroxyl radical quencher than allopurinol. However, data on allopurinol obtained in different studies do not always agree. Thus, the study of lipid peroxidation in rat kidney homogenates showed that the drug has nephrotoxicity, which is caused by an increase in the formation of cytotoxic oxygen radicals and a decrease in the concentration of antioxidant enzymes, which causes a corresponding decrease in the utilization of these radicals. According to other data, the effect of allopurinol is ambiguous. Thus, in the early stages of ischemia, it can protect the myocytes from the action of free radicals, and in the second phase of cell death, on the contrary, it contributes to tissue damage, while in the recovery period it again favorably effects the recovery of the contractile function of the ischemic tissue.

In conditions of myocardial ischemia, peroxide oxidation is inhibited by a number of drugs: antianginal agents (quarantil, nitroglycerin, obzidan, isoptin), water-soluble antioxidants from the class of sterically hindered phenols (eg, phenosan, inhibiting tumor growth induced by chemical carcinogens).

Anti-inflammatory drugs such as indomethacin, butadione, steroidal and nonsteroidal antiphlogistics (in particular, acetylsalicylic acid) have the ability to inhibit free radical oxidation, while a number of antioxidants - vitamin E, ascorbic acid, ethoxyquin, dithiothrenthol, acetylcysteine and diphenylenediamide have anti-inflammatory activity . The hypothesis, according to which one of the mechanisms of action of anti-inflammatory drugs is oppression of lipid peroxidation is quite convincing. Conversely, the toxicity of many drugs is due precisely to their ability to generate free radicals. Thus, the cardiotoxicity of adriamycin and rubomycin hydrochloride is associated with the level of lipid peroxides in the heart, the treatment of cells with tumor promoters (in particular, phorbol ester) also results in the generation of free radical oxygen forms, there is evidence in favor of the participation of free radical mechanisms in the selective cytotoxicity of streptozotocin and alloxan - they affect on pancreatic beta cells, anomalous free-radical activity in the central nervous system causes phenothiazine, stimulates lipid peroxidation rows in biological systems, and other drugs - paraquat, mitomycin C, menadione, aromatic nitrogen compounds, the metabolism in the body which are formed free radical forms of oxygen. The presence of iron plays an important role in the action of these substances. However, to date, the number of drugs that have antioxidant activity is much higher than that of pro-oxidant drugs, and the possibility that the toxicity of pro-oxidant drugs is not associated with lipid peroxidation, the induction of which is only the result of other mechanisms that condition them toxicity.

Indisputable inducers of free radical processes in the body are various chemical substances, primarily heavy metals-mercury, copper, lead, cobalt, nickel, although this is mainly shown in in vitro conditions, in experiments in vivo, the increase in peroxidation is not very high, and so far no correlation has been found between the toxicity of metals and the induction of peroxidation by them. However, this may be due to the incorrectness of the methods used, since there are practically no adequate methods for measuring peroxidation in vivo in vivo. Along with heavy metals, other chemicals are also prooxidant: iron, organic hydroperoxides, halogenated hydrocarbons, compounds that break down glutathione, ethanol, as well as ozone, and substances that are environmental pollutants, such as pesticides, and substances such as asbestos fibers , which are products of industrial enterprises. A number of antibiotics (for example, tetracycline), hydrazine, paracetamol, isoniazid and other compounds (ethyl, allyl alcohol, carbon tetrachloride, etc.) also have a prooxidant effect.

At present, a number of authors believe that the initiation of free radical lipid oxidation can be one of the reasons for the accelerated aging of the organism due to the numerous metabolic shifts described earlier.