Astaxanthin is a chain-breaking antioxidant with a strong antioxidant effect. The body can produce a small amount of oxygen free radicals in normal life activities such as respiratory chain electron transfer and oxidation of other substances in the body. When stimulated by chemical reagents, ultraviolet radiation, etc., a large amount of oxygen free radicals will be produced. These free radicals can cause lipid peroxidation, amino acid oxidation, protein degradation and DNA damage on biological membranes, and can also cause chain reactions of unsaturated fatty acids on cell membranes, thereby affecting the composition of cells. Astaxanthin can not only quench singlet oxygen and directly remove oxygen free radicals, but also block the chain reaction of fatty acids.
Studies have found that the ability of various carotenoids to quench molecular oxygen is ranked as follows: astaxanthin>α-carotene>β-carotene>bioxylin>zeaxanthin>lutein>bilirubin>biliverdin. Lee et al. compared the effects of five carotenoids and their derivatives, lutein, zeaxanthin, lycopene, isozeaxanthin and astaxanthin, with different numbers of conjugated double bonds, on quenching active oxygen in soybean oil photooxidation, and found that the ability to quench active oxygen increases with the increase of conjugated double bonds, and astaxanthin has the strongest quenching performance. Some researchers also used the thiobarbituric acid method, using heme proteins containing ferrous ions as free radical generators and linoleic acid as acceptors to detect the half-effective dose ED50 of each tested carotenoid and its derivatives and α-tocopherol (VE) to scavenge free radicals (see Table 1), and also found that astaxanthin has the strongest ability to scavenge free radicals.
In recent years, continuous research has also shown that the antioxidant effect of astaxanthin is more than 100 times stronger than that of α-tocopherol, and it is known as “super VE”. At the same time, astaxanthin can effectively prevent the peroxidation of phospholipids and other lipids. In addition, astaxanthin can also increase the activity of antioxidant enzymes and protein expression. Different doses of astaxanthin significantly increase the protein expression of peroxidase and superoxide dismutase in animal cells, and their biological activity is also significantly improved.