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Astaxanthin

Carotenoids are a group of naturally occurring organic pigments that are responsible, e.g., for the red, orange and yellow colours in the skin, flesh, shell and exoskeleton of aquatic animals. The major carotenoid in the aquatic system is astaxanthin. At least fifty (50) carotenoids have been found in human sera or tissues. Humans and other animals cannot synthesize carotenoids de novo and must obtain them from their diet. All carotenoids share common chemical features, such as a polyisoprenoid structure, a long polyene chain forming the chromophore, and near symmetry around the central double bond. The antioxidant mechanism of carotenoids includes singlet oxygen quenching, direct radical scavenging, and lipid peroxidation chain-breaking. The polyene chain of the carotenoid absorbs the excited energy of singlet oxygen, effectively stabilizing the energy transfer by delocalization along the chain, and dissipates the energy to the local environment as heat. Carotenoids, (e.g., astaxanthin), are potent direct radical scavengers and singlet oxygen quenchers and possess all the desirable qualities of such therapeutic agents for inhibition or amelioration of ischemia-reperfusion injury. It is recognized that astaxanthin possesses a strong antioxidation property against reactive oxygen species, which suggests a pharmaceutical applicability in protecting living cells against some diseases, such as, for example, cancer. Natural sources of dietary astaxanthin are in great demand by the aquacultural industries. Natural sources of dietary carotenoids that have been investigated for farmed fish include krill, crawfish, crustacean processing by-products, algae and higher plants. However, these natural sources tend to be too expensive and of limited availability and reliability to be commercially viable.

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