Table 3.
Physiologically important antioxidants and their functions.
| Antioxidant Type | Antioxidant Name | Functions |
|---|---|---|
| Enzymic antioxidants | Superoxide dismutase (SOD) | Converts to H2O2 and O2 |
| Catalase (CAT) | Converts H2O2 to 2H2O and O2 | |
| Glutathione peroxidase (GPx) | Detoxifies H2O2 and Lipid peroxides using reduced glutathione (GSH) producing the oxidised form of glutathione (GSSG) | |
| Glutathione reductase (GR) | Reduces GSSG to GSH | |
| Non-enzymic antioxidants | Ascorbic Acid (AA) | Detoxifies Superoxide radical, Hydroxyl radical, and H2O2 |
| Reduced Glutathione (GSH) | Neutralizes Superoxide radical, Hydroxyl radical, and H2O2; co-substrate for glutathione peroxidase | |
| α-Tocopherol | Detoxifies H2O2; protects against membrane lipid peroxidation (LPO) | |
| Ubiquinone | Detoxifies Lipid peroxides | |
| Thioredoxin (TRX) | General thiol redox control of protein activity via reversible disulfide formation | |
| Bilirubin | Effective in quenching/scavenging secondary oxidants produced during OS |