Abstract
The current situation in the world has brought humanity to the obvious threat of using nuclear weapons, which forces us to pay close attention to possible means of preventing the effects of ionizing radiation on the human body. These means can be classified as synthetic and natural. Synthetic drugs have certain protective properties, but have certain disadvantages – first, side effects on the human body. Herbal preparations, having a radio protective effect, have significantly less side effects compared to synthetic drugs, and deserve close attention.
A comparative analysis of synthetic and herbal preparations with radio protective action is presented. The qualitative composition of herbal preparations with radio protective action and their potential in reducing the negative impact of ionizing radiation on the human body are discussed. The comparative advantages and disadvantages of herbal preparations are analyzed,
Keywords: irradiation, natural and synthetic radio protectors, comparison, phyto preparations
Introduction
The current situation in the world has brought humanity to the obvious threat of using nuclear weapons which forces us to pay close attention to possible means of preventing the effects of ionizing radiation on the human body.
Therefore, the search for the socially adaptated methods for prevention and correcting the effects of irradiation of living organisms does not lose relevance.
Radio protectors
At the moment they can be separated into 2 main groups:
- synthetic and natural.
Synthetic preparations for the prophylactics and treatment of radiation injury are preventative drugs for the threat of radiation damage, after radiation therapy for cancer patients, in the work with radioactive substances. Synthetic drugs have certain protective properties, but have also certain disadvantages – first of all, side effects on the human body.
Conventionally, synthetic radio protectors can be divided into 2 groups:
1) radio protectors of short-term, one-stage action, are introduced into the body in a short time before irradiation:
- Sulfur compounds (mercaptoethylamine (MEA), cystamine, L-cysteine, gamma-phos, cystophos, etc.).
- Biologically active amines (serotonin, 5-methoxytryptamine, adrenaline).
- Preparations that disrupt the transport of oxygen in the body (methemoglobin-forming agents) or its utilization by cells (cyanides, nitrites, cyanophores).
- Derivatives of imidazole.
- Arylalkylamines.
- Indolylalkylamines.
- Certain alcohols (Batilol (glycerol esters),
- Other radioprotectors- various aminothiols (merkamin, propamine, aminoethylisothiouronium, individual carbohydrates etc.)
Mechanism of effect:
There are several basic hypotheses of the mechanism of action of radio protectors of this group.
1. Radio protectors cause a temporary decrease in the oxygen concentration in the tissue. It leads to reducing the possibility of formation of oxidizing radicals and peroxides during irradiation. Finally, this should lead to an increase in radio resistance.
2. Radio protectors can cause inactivation of free radicals: sulfur-containing radio protectors are able to bind radicals formed during radiation exposure - as a result, the oxidizing radicals do not affect the cell molecules.
3. Radio protectors can protect "critical" cell molecules: sulfur-containing radio protectors react with sulfhydryl groups of biologically important molecules and thereby "shield" them from the action of ionizing radiation.
4. Radio protectors as compounds that enhance the radio-resistance of biochemical systems.
Limitations
Absolute majority of radio protectors of one-stage action have a radio protective effect only if they are administered in sub-toxic doses. Various radiosensitive biochemical systems such as DNA biosynthesis, oxidative phosphorylation in cell microstructures, the formation of macroergic compounds in the nucleus of a cell, etc., are inhibited. The mechanism of temporary inhibition of biochemical systems bases on the ability of radio protectors to make chemical bonds with enzyme molecules by the temporal formation of a mixed-disulfide bond between the radio protectors and the protein-enzyme molecules containing the sulfhydryl group (dehydrogenase, caspase, insulinase, acetylcholine esterase, tissue cathepsines B1, H, L).
2) long-acting radioprotectors, are administered repeatedly, usually in small doses to radiation exposure:
- Amifostine;
- Calcium and Magnesium (as an antagonists of strontium, use per os);
- Dimethylsulfoxide (DMSO) (an antioxidant sulphur compound, is able to decrease inflammation and pain, exerts radioprotective effects through the facilitation of DNA double-strand break repair, but in toxic concentration);
- Zeolites and other clays (Kaolin, Red Clay, Bentonite, Fuller’s Earth, Montmorillonite. French Green Clay – as an absorbents of radionuclides, use per os)
Limitations:
Amifostine use leads to side effects (chills, dizziness, drowsiness, nausea and vomiting)
DMSO realizes its radioprotective effects in toxic concentration
Clays and zeolites, calcium and magnesium cannot be used everyday
Summing up, we are forced to state the fact that there is no effective and safe synthetic radio protector.
Herbal preparations, having a radio protective effect, have significantly less side effects compared to synthetic drugs, and deserve close attention
That is why special attention is paid to natural phyto preparations, which in comparison with the patented preparations have low toxicity, wide spectrum of activity and soft prolonged effect.
There are many data about radio protective functions of different plants, their complexes and biologically active compositions (like propolis, honey, plant extracts), but among them first flavonoids containing preparations are discussed.
Flavonoids are a large family of over 6,000 hydroxylated polyphenolic compounds.
Mechanism of their radio protective activity: they work as scavengers of free radicals and in this way prevent peroxide oxidation processes in the cells. There is a wide range of investigated representatives of flavonoids- from well-known (hesperidin, quercitin, rutin, genistein, kaempferol) to less frequently investigated deoxyschisandrin (SA) and schisandrin B. Many of them realize radio protective effect through an increase in the survival of irradiated animals, a decrease in the frequency of micronuclei in human lymphocytes, in reducing damage to chromosomes and membranes, improving immune system functions, but verifying the results is difficult due to the large differences in their production. Thus, there are use in research not only individual flavonoids, but their complexes and summary extracts of plant, or biologically active compositions such as propolis or honey and their derives. Nevertheless, flavonoids are able to decrease negative effects of irradiation, they have very low toxicity and very small side effects. Also other components of plants can be involved in the realizing of radio protective effect, therefore, further research into the radio protective properties of herbal preparations is needed.
Conclusion
Comparative analysis of potential abilities of synthetic and natural radio protectors shows the prevalence of natural substances or their complexes on the synthetic protectors from the point of view of their very low toxicity, mild complex effect and rare side effects.
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