Page 25 - Ranger SPM 2022 - Science

Science SPM Chapter 10 Chemicals in Medicine and Health

10.3 Antioxidant Substances

Definition of Antioxidant Substances
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1. Antioxidants are chemicals needed by our bodies to neutralise free radicals.

2. Antioxidants can slow down or stop the oxidation process.
3. The production of antioxidants in the human body depends on factors such as
age and health status.

4. Different foods provide different types of antioxidants as shown in Table 10.2.

Table 10.2 Antioxidants in food Form 4
Vitamin C Vitamin E
Antioxidant Beta carotene Lutein Lycopene (Ascorbic (Alpha-
acid) tocopherol)

Carrot, sweet Spinach, Tomato, Citrus Green
potato, broccoli watermelon, fruits and vegetables,
spinach papaya, vegetables beans,
orange cooking oil
Source

The Action of Antioxidants on Free Radicals

1. An antioxidant is a chemical compound which can be obtained through chemical
synthesis or from plants.
2. An antioxidant stabilises a free radical by completing the unpaired electron of
the free radical, as shown in Figure 10.7.
3. An antioxidant reacts with a free
radical to produce a more stable Unpaired
compound. This slows down or Antioxidant electron
inhibits oxidation.

4. In this way, damage to body cells Donate
can be prevented. electron

Figure 10.7 Action of antioxidant

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