Vitamin C, glutathione, and various enzymes have radioprotective effects against cellular damage caused by ionizing radiation. Vitamin C is an antioxidant that can scavenge reactive oxygen species produced by radiation and protect DNA and membranes. Glutathione is also a free radical scavenger that protects against radiation damage. Various enzymes also help scavenge free radicals produced by radiation. The presentation concludes that vitamin C, glutathione, and enzymes play an important role in mitigating the effects of ionizing radiation exposure.

1. B Y
MUHAMMAD BELLO GUSAU
(MNSBMB)
O F
D E P A R T M E N T O F A U T H O R I Z A T I O N & E N F O R C M E N T
Radioprotective Effect of
Vitamin C (L-Ascorbic Acid) and
Some Myriad Enzymes

2. Highlights
 Aim of the Study
 Background
 Biological Effect of Ionizing Radiation
 Scavenging Effect of L-Ascorbic Acid (Vitamin C)
 Side Effect of Vitamin C
 Radioprotective Effect of Glutathione and Myriad
Enzymes
 Conclusion
 Acknowledgement
 References

3. Aim of the Presentation
The aim of the presentation is to
learn the radioprotective effect of
Vitamin C/Glutathione and some
free radical scavengers .

4. Background
Radiation exist ubiquitously in the environment
since the Earth’s creation in soil, water and plants.
Radiation exposure is a concern in the health
industry and other occupations in the world.
Elevated radiation levels have been detected
following Chernobyl and Fukushima Daiichi
accidents on April 1986 and March 2011
respectively. This raised the need for finding out
efficient and reliable RADIOPROTECTORS
especially when a whole nation is exposed at high or
low levels for a long period

5. Background
 Vitamin C or L-ascorbic acid, or simply
ascorbate (the anion of ascorbic acid), a water
soluble vitamin is an essential nutrient for humans
and certain other animal species
 The name 'vitamin C' always refers to the L-
enantiomer of ascorbic acid and its oxidized forms
 Ascorbic acid is a weak sugar acid structurally
related to glucose. In biological systems, ascorbic
acid can be found only at low pH, but in neutral
solutions above pH 5 is predominantly found in the
ionized form, ascorbate.

6. Background
The biological role of ascorbate is to act as a
reducing agent, donating electrons to various
enzymatic and a few non-enzymatic reactions. The
one- and two-electron oxidized forms of vitamin C,
semidehydroascorbic acid and dehydroascorbic
acid, respectively, can be reduced in the body by
glutathione and NADPH-dependent enzymatic
mechanisms. The presence of glutathione in cells
and extracellular fluids helps maintain ascorbate in
a reduced state.

7. Background

8. Mechanism of Biological Damage by
Ionizing Radiation
 Direct damage to DNA
 Indirect damage via formation of
reactive chemical species
 End Result: disruption cell membrane
integrity, cellular chemistry and DNA
replication.

9. Biological Damage by Direct
Mechanism
• Ionizing event that occurs in nuclear
DNA can break single or double
strands.
• Damage may be (a) irreparable, or may
be (b) incorrectly repaired.
• Can result in (a) cell death at next
mitosis or (b) point mutation.

10. Direct Radiation Damage
Particle or EMR hits the DNA in the nucleus of a
replicating cell, either causes the cell to die during
mitosis, or induces a mutation

11. Biological Damage by Indirect Mechanism
• Ionizing radiation produces free
electrons in materials, and thus ion
pairs.
• Ion pairs combine to form reactive
chemical species.
• Reactive chemical species disrupt cell
membrane integrity, cellular chemistry and DNA
replication.

14. Radioprotective Effect of Vitamin C
 As seen earlier the effects of radiation are caused
mainly by the generation of reactive oxygen species
(ROS). These ROS interact with biological molecules
producing toxic free radicals leading to lipid
peroxidation and DNA damage
 Lipid peroxidation has effects on biological
membranes and studies on lipid peroxidation can
provide important information about detrimental
effects of gamma-radiation.

15. Radioprotective Effect of Vitamin C
 ROS can also alter the balance of endogenous
protective systems, such as glutathione and
enzymatic antioxidants (SOD, CAT and GPx)
defence system, thus the endogenous antioxidant
defences are inadequate to reduce the radiation
induced free radicals.
 Appropriate antioxidant intervention may inhibit
or reduce free radical toxicity and thus offer
protection against radiation. Several dietary anti-
oxidants have been reported to decrease free
radical attack on biomolecule.

16. Radioprotective Effect of Vitamin C
 Numerous studies have examined the radioprotective
effect of antioxidant free radical scavengers, which
protect the cell and its organic constituent molecules
from free radicals damage
 Vitamin C have been reported to be an effective
antioxidant and free radical scavenger and, in vivo and
in vitro conditions, reduce oxidative and free radical-
induced damage to DNA and membranes in biological
systems
 Vitamin C is an important dietary factor that has been
reported to decrease the adverse effect of ROS and RNS
by scavenging radicals or by neutralizing an array of
these radicals.

17. Radioprotective Effect of Vitamin C
Vitamin C functions as a free radical scavenger of
active and stable oxygen radicals as have been
shown to protect several biological systems
against ionizing radiation. The radioprotective
effect of L-ascorbic acid seems to be due to its
interaction with radiation-induced free radicals

18. Radio protective Effect of Glutathione
and Other Myriad Enzymes
Glutathione also known as Gamma-L-Glutamyl-L-
Cysteinylglycine is a substance produced naturally
by the liver. It is also found in fruits, vegetables,
and meats.
People take glutathione by mouth for treating
cataracts and glaucoma, preventing aging, treating
or preventing alcoholism, asthma, cancer, heart
disease (atherosclerosis and high
cholesterol),hepatitis, liver disease, diseases that
weaken the body’s defense system and chronic
fatigue syndrome, memory loss, Alzheimer’s
disease, osteoarthritis, and Parkinson’s disease.
Glutathione is also used for maintaining the body’s
defense system (immune system) and fighting
metal and drug poisoning

19. Structure

20. Radioprotective Effect of Glutathione
Among the functions of glutathione is its role as
free radical scavenger of active and stable oxygen
radicals as have been shown to protect several
biological systems against ionizing radiation

21. Glutathione and Myriad Enzymes

22. Glutathione and Myriad Enzymes

23. Scavenging Effect of Myriad Enzymes

24. Conclusion
The radioprotective and mitigative effects of
Vitamin C and Myriad Enzymes against
cellular damage caused by ionizing radiation
and oxidative stress has been proven to play a
pivotal role in a situation where the effects of
ionizing radiation are to be controlled.

25. Acknowledgement
 Special thanks are due to Department of Biochemistry
and Medical Laboratory Department of Usmanu
Danfodiyo, University, Sokoto for their academic and
practical equipment support
 Gratitude is expressed to my able Director and his
assistant in the persons of Dr. Yau Idris and Mr. Tukur A.
Faru for their guidance, directions and moral support
 Special thanks to DRS who indirectly but tremendously
contributed to this seminar
 Gratitude is also expressed to DAF for moral support
 My profound gratitude to all the people present here.

26. References
 El-Habit OH, Saada HN, Azab KS, Abdel-Rahman M,
El Malah DF. The modifying effect of β-carotene on
gamma radiation induced elevation of oxidative
reactions and genotoxicity in male rats. Mutat Res
2000;466:179-86
 El-Nahas SM, Mattar FE, Mohammed AA.
Radioprotective effect of Vitamin C and E. Mutat Res
1999; 301:143-7
 Mallikarjun Rao KV, Jagetia GC, Ascorbic Acid
treatment enhances the wound healing in mice
exposed to radiation. Indian J Radiat Res 2004;1:24

27. References
 Maurya DK, Devasagayam TP, Nair CK. Some novel
approaches for radioprotection and the beneficial
effects of natural products. Indian J Exp Biol
2006;44:93-114
 Naidu KA. Vitamin C in human health and disease is
still a mystery? An Overview. Nutr J 2003;2:7-17
 Tarladacalisir YT, Kanter M, Uygun M. Protective
effects of vitamin C on cisplatin-induced renal
damage: a light and electron microscopic study. Ren
Fail 2008;30:1-8

28. Reference
 Weiss JF, Kumor KS, Walden TL. Advances in radio-
protection through the use of combined agent
regiments. Int J Radiat Biol 1998; 57:709-22
 Wilson RL. Free radical repair mechanisms and the
interaction of glutathione and vitamin C and E. In:
Nyga OF, Simic MG, editors. Radioprotectors and
anticarcinogens. NewYork: Academic Press; 1983.
p.1-23.