Free Radical; Defense From Aging

Rajkumar Kirtania

M.Sc,4th semesterRegd. No.-240313020

Exam Roll No -151303020

INDIAN INSTITUTE OF ENGINEERING

SCIENCE AND TECHNOLOGY,SHIBPUR

DEPT. OF CHEMISTRY

Free Radicals.

Various Sources.

Harmful Effect.

Defense via Antioxidant.

CONTENT2

Free Radicals are molecules with an unpaired electron and are important

intermediates in natural processes.

Involving cytotoxicity, control of vascular tone, and neurotransmission.

Free radicals are very unstable and react quickly with other compounds,

and try to capture the needed electron to gain stability.

A chain reaction thus gets started.

FREE RADICAL 3

How Free Radicals Form 4

Sources of free Radicals

Cellular

SourcesEnzymic

Sources

Environmental

Sources

Mitochondria

Endoplasmic

reticulum

Cytochrome

oxidases

Xanthine

oxidase

Ionizing

radiation

Pollution

Membrane

NADPH

Oxidases

Source of Free Radical

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Environmental sources

Exposure to ionizing radiations like gamma rays, x-rays, and ultraviolet rays excite the electrons in many atoms, thereby generating large amounts of free radicals.

H2OU.V. Rays HO▪ + H+

Oxygen free radicals in the atmosphere considered as pollutants

Interaction with chemicals, automobile exhausts fumes, smoking of cigarettes, cigars, beedie

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Harmful Effect of Free Radical

Cancer

Cerebrovascular disease

Heart disease &Stroke

Diabetes mellitus

Sunburn

Cerebrovascular disease.

Osteoporosis

Crohn's disease

Behcet's disease

Arteriosclerosis & atherosclerosis

Senility

Aging

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FREE RADICAL THEORY OF AGING

In 1956s Dr. Denham Harman proposed that-

Cells continuously produce free radicals by normal metabolism and oxidation of organic

compounds and these free radicals damage cellular macromolecules ( like DNA , lipid

, proteins ) and due accumulation of these damage over time period cause aging.

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Mitochondrial free radical theory of aging

In 1972s, Denham Harman modified his theory-

About 95% energy of a cell is produce in mitochondria and about 97% - 99% of oxygen is use in energy formation and 1%- 3% oxygen is utilize in reactive oxygen species formation.

It states that reactive oxygen species (ROS ) are produce in mitochondria during ETC cycle and they cause damage to macromolecules including lipid , protein, DNA of mitochondria and nucleus which lead to aging .

DNA Damage

RNA damage

Protein Damage

Lipid Damage

Reactive

species

AGING

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Formation of thymine dimer

Oxidative damage to DNA

Modification of purines – 8-hydroxy-deoxyguanosine

Marker of the oxidative damage to DNA

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Antioxidant Vitamins --

Vitamin E-It is a fat soluble vitamin and prevent peroxidation of

lipid by donating of electrons to free radicals

In absence of vitamin ‘E’ In presence of vitamin ‘E’

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Vitamin C:Vitamin C protects watery components in the body (fluid in the blood) against free radical damage.

Vitamin C also is especially good at stopping free radicals air pollution and cigarette smoke.

In addition, vitamin C may also restore oxidized vitamin E to its active state

Ascorbic acid is special because it can transfer a single electron, owing to the resonance-stabilized nature of its own radical ion called, semidehydroascorbate. The net reaction is…

RO • + C6H7O6− → RO- + C6H7O6

• → → ROH + C6H6O6

It suppresses the formation of carcinogens i.e. cancer.

protecting tissues against oxidative damage.

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CONCLUSION

To Avoid Exposure Of Free Radical ,we Should Avoid Sunshine & Our Diet

Should Be Full Of Vitamins With an Antioxidant

Monitoring and rapid detection of free radical is necessary to combat the spread of

various diseases

So if we can intensify our knowledge regarding free radicals & go deep into it we

can easily prove the proverb “PREVENTION IS BETTER THAN CURE”

Prevention Is Better Than Cure

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References

Wikipedia

C. J. Rhodes, An overview of the role of free radicals in biology.

CRC Handbook of Free Radicals and Antioxidants, 1989, 1: 209-221.

P, Larsen, "Aging and resistance to oxidative damage in Caenorhabditis

elegans". Proc Natl Acad Sci U S A, 1993, 90 (19):8905-9.

Exercise, Oxidative Damage and Effects of Antioxidant Manipulation

(review). Journal of Nutrition, 1992, 122(3): 766-73.

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ACKNOWLEDGEMENT

I would like to acknowledge

My project supervisor, Dr. Jhuma Ganguly,

Head of the department Prof. P. K. Nandi,

All the teachers of our department ,

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