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Updated: Aug 6, 2026
11:56
A Rapid and Specific Microplate Assay for the Determination of Intra- and Extracellular Ascorbate in Cultured Cells
Published on: April 12, 2014
Ascorbate is an outstanding antioxidant in human blood plasma
Summary
Ascorbate (vitamin C) is the primary antioxidant protecting human blood plasma lipids from oxidative damage. Its depletion makes plasma highly vulnerable to peroxidative injury, highlighting its crucial role in preventing disease.
Area of Science:
- Biochemistry
- Human Physiology
- Oxidative Stress Research
Background:
- Human blood plasma contains various antioxidants that combat oxidative stress.
- The sequential consumption and efficacy of these antioxidants against peroxyl radicals were previously unknown.
- Lipid peroxidation is a key indicator of oxidative damage to cell membranes.
Purpose of the Study:
- To determine the specific role of ascorbate (vitamin C) in protecting plasma lipids from peroxidative damage.
- To identify the most effective aqueous-phase antioxidant in human blood plasma.
- To elucidate the contribution of other plasma antioxidants like protein thiols, bilirubin, urate, and alpha-tocopherol.
Main Methods:
- Exposure of human blood plasma to a constant flux of aqueous peroxyl radicals.
- Monitoring the consumption order of different antioxidants.
- Assessing the onset of detectable lipid peroxidation in plasma with and without specific antioxidants.
Main Results:
- Ascorbate is the sole plasma antioxidant that completely protects lipids against peroxidative damage induced by aqueous peroxyl radicals.
- Detectable lipid peroxidation initiates only after complete ascorbate depletion.
- Plasma lacking ascorbate is highly susceptible to oxidant stress and lipid peroxidation, while other antioxidants do not offer complete protection.
Conclusions:
- Ascorbate is the most potent aqueous-phase antioxidant in human blood plasma.
- Ascorbate plays a critical physiological role in protecting against diseases and degenerative processes linked to oxidant stress.
- Protein thiols, though oxidized early, are inefficient radical scavengers and primarily consumed via autoxidation.
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