Introduction Oxidation What are antioxidants? Antioxidants Source of Antioxidants Antioxidants produced by Plants Major Antioxidant compounds in Plants Fruits and Vegetables with highest Antioxidant content Conclusion

1. By: Asim Zahoor
PLANTS AS ANTIOXDANTS

2. Outline
• Introduction
• Oxidation
• What are antioxidants?
• Antioxidants
• Source of Antioxidants
• Antioxidants produced by Plants
• Major Antioxidant compounds in Plants
• Fruits and Vegetables with highest Antioxidant
content
• Conclusion

3. Introduction
•Although oxidation reactions are crucial for life,
they can also be damaging to cells.
•This process causes health problems like aging,
cancer, high blood pressure and hardening of
arteries, arthritis, asthma, Parkinson, Alzheimer
disease and infertility.
•Oxidation also causes food spoilage.
•Most often, the best strategy is the addition of
antioxidants.
•Most Antioxidants are reducing agents.

5. Oxidation
•Oxidation is a chemical reaction involving the
loss of electrons which can produce free
radicals.
•Oxidants are usually chemical substances with
elements in high oxidation states (e.g.,H2O2) or
highly electronegative elements (O2, F2, Cl2, Br2).
•These radicals can start chain reactions.
•When the chain reaction occurs in a cell, it can
cause damage or death to the cell.

8. Antioxidants
• An antioxidant is a molecule that inhibits
the oxidation of other molecules.
• Antioxidants terminate these chain
reactions by removing free radical
intermediates, and inhibit other oxidation
reactions and in turn oxidizing
themselves.
• Example: Reducing agents such as thiols,
ascorbic acid (vitamin C), or polyphenols.

10. Source of Antioxidants
1. Supplements
2. Diet
Recent research suggests there is little benefit
from taking diet supplements, even harmful and
toxic.
Fruits, vegetables, and grains rich in dietary
antioxidants provide a better way to boost
antioxidants intake.

11. Antioxidants produced by Plants

12. Major Antioxidant compounds
in Plants
1. Enzymes
Superoxide dismutase (SODs) :
• SOD isozymes are present in chloroplasts, the
cytosol and mitochondria.
• It catalyzes the decomposition of hydrogen
peroxide into Water and Oxygen
Glutathione (GSH)
Participate directly in the neutralization of free
radicals and reactive oxygen compounds, as well
as maintaining exogenous antioxidants such as
vitamins C and E in their reduced (active) forms.

13. Glutathione peroxidase
Glutathione peroxidase uses glutathione as
substrate and catalyzes the reduction of
hydrogen peroxide and lipid hydroperoxide.
2. Minerals:
• Minerals are elements that originate in
the soil and cannot be created by living
things
• Selenium is the only mineral produced
by Plants.
• The richest plant sources of selenium is
Brazil nut

14. 3. Low molecular weight and High molec
ular weight compounds:
• High molecular weight compounds include
albumin, cariplasmin, and transferrin.
• Low molecular weight antioxidants are divide
d into lipid soluble antioxidants (polyphenols,
Tocopherol, and ascorbic acid etc.) and water
soluble antioxidants (some polyphenols).
• Both types of these compounds act as
reducing agents, free radical scavengers, and
quenchers of singlet oxygen formation.

15. 4. Vitamins:
Vitamin A:
•Vitamin A is a group of unsaturated nutritional
organic compounds that includes retinol, retinal,
retinoic acid, and several provitamins.
Vitamin C:
•Ascorbic acid is a redox catalyst which can
reduce, and thereby neutralize, reactive oxygen
species such as hydrogen peroxide and is also a
substrate for the redox enzyme ascorbate
peroxidase, a function that is particularly
important in stress resistance in plants.
•Vitamin E:

16. Vitamin E:
•Vitamin E is the collective name for a set of eight
related tocopherols and tocotrienols, which are fat
-soluble vitamins with antioxidant properties.
•The functions of vitamin E are less understood
although it has been suggested that these vitamins
protect from oxidation by protecting fatty acids.

17. Fruits and Vegetables with highest
Antioxidant content

18. Conclusion
•Oxidative stress causes various diseases
and food spoilage.
•Antioxidants reduce the stress caused by the
reactive oxidizing species.
•Plants are good source of Antioxidants intake.