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The Chemistry of Antioxidants

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Remember that NAD is used in animal cells to shuttle electrons in cellular metabolism ... It also plays a critical role in the recycling of vitamin E and other ... – PowerPoint PPT presentation

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Title: The Chemistry of Antioxidants


1
The Chemistry of Antioxidants
  • Steve Goldrick
  • Traci Pawlitschek
  • Matt Hammons
  • Erin Pflueger
  • Kristin Crandall

2
What is an antioxidant and a free radical?
  • A free radical is defined as any molecule with at
    least one unpaired electron.
  • Free radicals are a common byproduct of the
    normal chemical reactions that occur in cells.
  • They can also be formed by exposure to
  • alcohol
  • insecticides
  • radiation
  • chemicals in the home or at work
  • excessive amounts of sunlight
  • high fat diet or eating fried foods
  • strenuous exercise
  • tobacco smoke
  • Antioxidants are molecules ingested or made by
    our bodies to neutralize free radical damage.

3
Electron shuttle
  • Remember that NAD is used in animal cells to
    shuttle electrons in cellular metabolism
  • Your NAD (nicotinamide adenine dinucleotide) is
    reduced in 5 separate steps to NADH during
    glycolysis, the transition reaction (pyruvate
    oxidation step), and the Krebs cycle.


4
Production of a free radical
  • Macrophage metabolism is the most common way of
    producing the free radical superoxide
  • An enzyme cascade (the respiratory burst) uses
    oxygen gas to produces the tools used to destroy
    phagocytized materials (e.g. bacteria, spent
    organelles)
  • Superoxide is the first molecule produced in the
    cascade
  • Due to a lack of NADH to make the oxidizing
    substances in the pathway, the cascade fails to
    complete and superoxide leaks out

5
Problem of Superoxide
  • Superoxide can damage cell membranes leading to
    cancer, or oxidize low density lipoproteins in
    cell membranes leading to atherosclerotic
    plaques.

6
How do Antioxidants help defense???
  • VITAMIN C A powerful water-soluble antioxidant
    that circulates freely within the plasma. It
    also plays a critical role in the recycling of
    vitamin E and other antioxidants.
  • Smoking lowers vitamin C metabolism creates
    high oxidative stress
  • VITAMIN E A fat-soluble antioxidant that is
    transported primarily in LDL-cholesterol which
    helps to prevent the oxidation of the fatty acids
    and proteins.
  • Prevents artherosclerotic plaques by preventing
    LDL-cholesterol oxidation.
  • VITAMIN A Certain carotenoids are able to
    destroy a form of oxygen called singlet oxygen.
  • Are too many antioxidants bad for you????
  • Conflicting research!

7
ANALOGY
  • Military supplying
  • Jumping on the grenade
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