Free radicals are produced during normal metabolism but can damage cells. Antioxidants help destroy free radicals and prevent this damage. Sources of antioxidants include vitamins C and E, beta-carotene, selenium, and phytonutrients found in plants. Lipid peroxidation occurs when free radicals damage lipids and can affect food quality, nutrition, and health, causing conditions like heart disease. Antioxidants have therapeutic implications, as they may help treat or prevent cardiovascular disease, certain cancers, brain injuries, strokes, neurodegenerative diseases, and liver damage by reducing oxidative stress.

1. Antioxidants and their therapeutic implications
Although oxygen is essential for life, excess
oxygen can have harmful effects. When
oxygen is metabolised by the body it creates
substances called free radicals which cause
damage to our cells.
Free radicals can also be created by exposure
to pollution, cigarette smoke and fatty foods.

2. Excessive amounts of free radicals are thought
to be related to the development of conditions
such as:-
 Heart and liver disease
 Some cancers,
 Arthritis,
 Accelerated ageing
 Eyesight deterioration.

3.  The body has its own natural defences
against free radicals, but these systems
can sometimes be overwhelmed.
 Antioxidants are naturally occurring
nutrients in food or chemical compounds
which help destroy free radicals and
minimise damage to our cells. they can delay
the start or slow the rate of lipid per oxidation
reaction in food systems.

4. SOURCES OF ANTIOXIDANTS
 VITAMIN-E
 VITAMIN-C
 BETA-CAROTENE
 SELENIUM
 PHYTONUTRIENTS

5. Vitamin E
It is one of the strongest antioxidants, and
can be found in nuts, oils, green vegetable
and wholegrain. It helps prevent disease by
destroying free radicals and protecting
DNA in cells from damage.

6. Vitamin C
It has a dual role, in that it helps the body absorb
vitamin E and protects it from harm. Citrus
fruits and vegetables are the best food sources of
vitamin C. Smokers in particular should ensure
they get enough vitamin C, as it helps fight
toxins and free radicals from cigarette smoke.

7. Beta-carotene
It is converted by the body into vitamin A. It
benefits skin and hair, helps maintain strong
bones and protects against eye problems.
Beta-carotene is found mainly in red- and
orange-coloured fruits and vegetable.

8. Selenium
It is the main mineral antioxidant. It is involved
in the production of powerful enzymes which
‘mop up’ free radicals and deactivate them.
Selenium is found in brazil nuts, seafood and
red meat.

9. Phytonutrients
They are naturally occurring plant chemicals
which don’t have any nutritional value, but
which have the ability to act as antioxidants.
Different types of phytochemical occur in
different foods: flavonoids are found in
abundance in fruit, vegetables, dark chocolate
and red wine (which should be consumed in
moderation); tea and grapes are a good source of
polyphenols; allium sulphur compounds are
found in onions, leeks and garlic.

10. lipid per oxidation:
 Lipid per oxidation refers to the
oxidative degradation of lipids. It is the process in
which free radicals "steal" electrons from the
lipids in cell membranes are formed resulting in
cell damage.

11. Mechanism of lipid per
oxidation

13. PROCESS INVOLVED IN THE MECHANISM OF
LIPID PER OXIDATION
 Initiation: Initiation is the step in which a fatty
acid radical is produced. The most notable
initiators in living cells are reactive oxygen
species(ROS), such as OH· and HO2, which
combines with a hydrogen atom to make water
and a fatty acid radical.
 Propagation: The fatty acid radical is not a very
stable molecule, so it reacts readily with
molecular oxygen, thereby creating a peroxyl fatty
acid radical. This too is an unstable species that
reacts with another free fatty acid, producing a
different fatty acid radical and a lipid peroxide.

14.  Termination: When a radical reacts with a
non-radical, it always produces another radical,
which is why the process is called a "chain
reaction mechanism." The radical reaction stops
when two radicals react and produce a non-
radical species. Living organisms have evolved
different molecules that speed up termination by
catching free radicals and, therefore, protecting
the cell membrane. One important
such antioxidant is vitamin E. Other anti-
oxidants made within the body include the
enzymes superoxide dismutase, catalase,
and peroxidase.

15. EFFECTS OF LIPID PER OXIDATION:
 Flavour Quality Loss:
 Rancid flavour
 Changes of colour and texture
 Consumer Acceptance
 Economic loss
 Nutritional Quality Loss:
 Essential Fatty Acids
 Vitamins
 Health Risks:
 Toxic Compounds
 Growth Retardation
 Heart Diseases

16. Ideal Antioxidants
No harmful physiological effects
Not contribute an objectionable flavor, odor, or
color to the fat
Effective in low concentration
Fat-soluble
Carry-through effect  No destruction during
processing
Readily-available
Economical
Not absorbable by the body

17. Kinds of Antioxidants
Natural antioxidants:
 Tocopherols
 Nordihydroguaretic Acid (NDGA)
 Sesamol
 Gossypol
Synthetic antioxidants:
 Butylated Hydroxy Anisole (BHA)
 Butylated Hydroxy Toluene (BHT)
 Propyl Gallate (PG)
 Tertiary Butyl Hydroquinone (TBHQ)

18. Therapeutic implications of antioxidants
 Antioxidant in cardiovascular disease
 Antioxidant therapy in cancer
 Antioxidants in Brain injury:
 Antioxidants in stroke treatment :
 Antioxidants in neurodegenerative diseases
 Antioxidants in apoptosis
 Antioxidants in liver damage

19. Antioxidant therapy in cardiovascular disease
Antioxidant therapy may inhibit atherosclerosis
and thereby prevent the clinical complications of
the disease such as CAD, and in particular, MI.
Free radicals are formed by several exogenous
processes such as radiation and tobacco smoke,
and are the endogenous natural by-products of
cellular metabolism. these radicals tend to
damage protein, DNA, lipids and carbohydrates
as result cell death.

21. Antioxidant therapy in cancer
The following is a list of common antioxidants
used in cancer programs.
 Beta carotene
 Vitamin C
 Vitamin E
 Selenium
 Lipoic acid
 Poly MVA

22. Beta carotene
Beta-carotene is a form of vitamin A. Vitamin A
is a strong immune booster. It stimulates the
activity of immune cells against tumor cells. Has
been shown to inhibit the promotion of caner,
while beta carotene (precursor to vitamin A)
inhibits the initiation of cancer. Beta-carotene
can decrease the amount of damage free radicals
do to a cell's DNA. Such DNA damage is
thought to be one mechanism that causes cancer,
and indeed, some early studies suggested that
beta-carotene might reduce the risk of cancer.

23. Vitamin C
It is known that vitamin C acts as an antioxidant
and free radical scavenger that reacts directly with
super oxide, hydroxyl radicals, and singlet oxygen
produced during normal cellular metabolism.
Oxygen is necessary for life. Oxygen also comes
in several radical forms that have been implicated
in both initiation and post initiation stages of the
carcinogenic process as well as in invasion and
metastatic processes. Aside from its antioxidant
properties, there is no single universal accepted
and proven explanation for vitamin C's cancer
fighting properties.

24. Vitamin E
Vitamin E is an important fat-soluble
antioxidant, vitamin E's preventive role in
cancer has been well proven.
 Highly malignant melanoma cell in vitro has been
shown to be converted into differentiated (normal) cell
after 3 days of exposure to Vitamin E succinate.
 Ovarian and cervical cancer - vitamin E slow downs the
mitotic activity of cancer cell but normal cell don't get
affected.
 Glioma tumor cells (present in the brain) are also more
effective attacked by vitamin E succinate, probably
because of its better penetration of blood bran barrier.
 Vitamin E succinate enhances radiation in cancer cell
and protects the normal cell.

25. Selenium
 It is a powerful antioxidant with a central role in
the protection of tissues from the damaging
effects of oxygen free radicals. The use of
selenium compounds as a cancer treatment
predates most conventional treatments currently
in use.
 200 mcg of selenium a day has been shown to
reduce cancer death by 50% and prostate cancer
by 62% after 4 years. Cancer patients are often
found to be deficient in selenium. Selenium
works synergistically with vitamin E.

26. Lipoic acid
It is called the universal antioxidant for its
ability to dissolve well in water and in fat
environment, Lipoic acid increase the
effectiveness or potency in other antioxidants. It
can cross the blood brain barrier while others
cannot .One of the most beneficial effects of
alpha Lipoic acid is its ability to regenerate
other essential antioxidants such as vitamins C
and E, coenzyme, and glutathione.

27. Poly MVA
 This is an alpha Lipoic acid complex with
palladium. It is a non-toxic polynucleotide
reductase named POLYDOX (USA trials),
Poly-MVA (Canada and Mexico) or LAPd by
some researchers.
 The element platinum is very lethal to cancer
cells, but also very toxic to humans.
 It's close relative: palladium, however, is
nontoxic in its present form.
 The MVA stands for minerals, vitamins, and
amino acids. LAPd stands for Lipoic
acid/Palladium complex.

28. Antioxidants in Brain injury:
Antioxidants are commonly used
as medications to treat various forms of brain
injury. Here, superoxide dismutase mimetics,
sodium thiopental and propofol are used to
treat reperfusion injury and traumatic brain
injury.
Antioxidants in stroke treatment :
Experimental drug NXY-059 and ebselen are
being applied in the treatment of stroke.

29. Antioxidants in neurodegenerative diseases
Antioxidants are also being investigated as
possible treatments for neurodegenerative
diseases such as Alzheimer's disease ,
Parkinson's disease, and amyotrophic
lateral sclerosis.

30. Others:
 These compounds appear to prevent
oxidative stress in neurons and prevent
apoptosis and neurological damage.
 They may prevent damage to the liver
caused by excessive alcohol.

31. Submitted By:
Manish Kumar
M.Pharm
Pharmacology
Mangalayatan
university
Thank you