2. Radiation Protective agents
Radioprotective agents are the compounds that
are administered before radiation to reduce the
cell damage and cell death caused by ionizing
radiation.
These compounds are used in the patients
undergoing radiotherapy, radiation therapy staff,
and other involved healthcare staff in the event of
job-related incidents in radiation departments.
3. What Are The Different Types of
Radiation?
Radiation is a type of energy that can travel
through space.
Sometimes it travels in the form of a wave.
That’s called electromagnetic radiation.
Sometimes, it travels as a beam of fast-moving
particles. That’s called particle radiation.
4.
5.
6. Radiation hazard on mankind
• Biological effect of ionizing radiation begins
with ionization of atom at molecular level.
• The high energy radiation breaks the
molecular bond of cell and results in
alteration leading to cellular apoptosis along
with several deleterious effects.
• When an ionizing radiation falls on the
biological system, it produces acute and
chronic symptoms
7.
8. Mechanism of radiation injury
• When ionizing radiation falls on biological
system it acts as an important source for the
generation of free radicals and reactive oxygen
species (ROS) like O2-, OH-, H2O2.
• These free radicals are very unstable and react
quickly with other components of cellular
system, to capture the needed electron to
gain stability.
9.
10. Characteristics of ideal radioprotector
• Effective in significant protection against the
effects of ionizing radiation
• General protective effect on the majority of
organs,
• Acceptable toxicity profile
• Protective time-window effect and
• Possess compatibility with the wide range of
other drugs that are available to patients or
personnel
12. Mechanism of Radioprotective Agents
Radioprotective compounds reduce the adverse effects of
radiation on the body tissues through the following
mechanisms:
1. Entrapment of the free radicals;
2. Donating hydrogen to damaged molecules;
3. Induction of hypoxia and decreased production of active
species with molecular and atomic oxygen;
4. Stimulating the proliferation and differentiation of stem
cells in the hematopoietic system;
5. Increasing the activities of antioxidant enzymes in the
organs;
6. DNA binding and sustaining
13. Curcuma longa
• Curcumin (diferuloyl methane), a yellow pigment present in
the rhizomes of turmeric, has been used in Southeast Asia to
give yellow color and flavor to curries.
• Recently, it has been evaluated for its radioprotective and
radiosensitizing activities.
• curcumin in cancer will be able to kill the tumor cells
effectively by enhancing the effect of radiation and, at the
same time, protect normal cells against the harmful effects
of radiation.
• The radioprotective effect might be mainly due to its ability
to reduce oxidative stress and inhibit transcription of genes
related to oxidative stress and inflammatory responses,
whereas the radiosensitive activity might be due the up
regulation of genes responsible for cell death.
14. Gingko biloba
• G. biloba is a unique tree species with no close living
relatives and extracts of its leaves contain antioxidant
compounds including glycosides and terpenoids known as
ginkgolides and bilobalides.
• Antioxidant extracts of the leaves of the Gingko biloba tree
may protect cells from radiation damage.
• It neutralize the free-radicals and oxidizing agents produced
in the cells by the radiation and so prevent them from
undergoing apoptosis.
15. Panax Ginseng
• Panax ginseng contains water-soluble compounds, including
polysaccharides, proteins, and saponins.
• Pure polysaccharide compounds are extracted from a plant
known as janas to increase the number of hematopoietic
cells and cytokines (e.g., IL-12) in the bone marrow .
• Ginseng stimulates the secretion of cytokines (e.g., GM-CSF
and CFU-S), as well as the proliferation of blood progenitor
cells in the bone marrow. Furthermore, use of ginseng has
been shown to increase platelet, lymphocyte, and neutrophil
counts and stimulate the immune system with its potent
antioxidant properties
16. Ginseng
• Panax ginseng contains water-soluble compounds, including
polysaccharides, proteins, and saponins.
• Pure polysaccharide compounds are extracted from a plant
known as janas to increase the number of hematopoietic
cells and cytokines (e.g., IL-12) in the bone marrow .
• Ginseng stimulates the secretion of cytokines (e.g., GM-CSF
and CFU-S), as well as the proliferation of blood progenitor
cells in the bone marrow. Furthermore, use of ginseng has
been shown to increase platelet, lymphocyte, and neutrophil
counts and stimulate the immune system with its potent
antioxidant properties
17. Tinospora cordifolia
• It contains alkaloids, diterpenoid lactones, glycosides,
steroids, sesquiterpenoid, phenolics, aliphatic compounds,
and polysaccharides
• It contains cordifolioside-A, which posses radioprotective
and cytoprotective activity
• The ability to prevent radiation damage, which may be due
to free radical scavenging.
• The protection from irradiation effects may be as a result of
several factors, such as the prevention of damage through
inhibition of free radical generation or efficient scavenging
of free radicals, repair of DNA, membrane, and other
damaged target molecules, and the replenishment of
severely damaged or dead cells.
18. Mentha piperita
• Commonly known as peppermint shows the radioprotective
activity on the vital radiosensitive organs.
• Mint contains both polar and non-polar compounds with
radioprotective effects.
• Among the non-polar compounds it is quite possible that the
antioxidant and anti-inflammatory compounds like menthol,
eucalyptol, luteolin, β-myrcene, menthone, limonene, rosmarinic
acid, and cineole may have been responsible for the observed
effects. Among the water-soluble compounds, mint contains
flavanoids like rutin, hesperidin, caffeic acid, carnosic acid,
carnosol, and rosmarinic acid, which have all been reported to
possess radioprotective effects.
• The radioprotective effects are possibly due to free radical
scavenging, antioxidant, metal chelating, anti-inflammatory,
antimutagenic, and enhancement of the DNA repair processes.
