The Chemistry of Antioxidants

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The Chemistry of Antioxidants

• Steve Goldrick
• Traci Pawlitschek
• Matt Hammons
• Erin Pflueger
• Kristin Crandall

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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.

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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.

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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

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Problem of Superoxide

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

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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!

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ANALOGY

• Military supplying
• Jumping on the grenade