Astaxanthin belongs to a group of compounds called carotenoids. While B-carotene is a vitamin A precursor, astaxanthin cannot be converted to vitamin A. In laboratory studies, astaxanthin has been reported to be typically at least 10 times more potent as an antioxidant than the other standard carotenoids such as canthaxanthin, b-carotene, lutein, lycopene, tunaxanthin and zeaxanthin. Astaxanthin provides the rich pink color observed in various aquatic species including salmon, crabs, lobster, shrimp and even some nonaquatic species such as the flamingo (whose diet includes some astaxanthin-producing organisms).
During the late nineties, antioxidant research surged, particularly on carotenoidsthat fat-soluble group of pigments widely distributed in plants and animals. Carotenoids have demonstrable antioxidant abilities and are thought to be important in helping to prevent numerous diseases. Some of the more exciting new research is being done on age-related macular degeneration. As a member of the carotenoid group xanthophylls, astaxanthin possesses oxygen in its chemical structure. Other xanthophylls include canthaxanthin, cryptoxanthin, lutein and zeaxanthin. Some of the better-known carotenoids of other groups are beta-carotene (present in carrots), lycopene (in tomatoes) and lutein (in spinach). Unlike beta-carotene, astaxanthin lacks pro-vitamin A activity.1
Antioxidant Effect of Astaxanthin
on Phospholipid Peroxidation in Human Erythrocytes
British Journal of Nutrition 2011 (Jun); 105 (11): 1563–1571 (Epub Jan 31)
This study investigated the effect of astaxanthin on phospholipid hydroperoxides, which are known to accumulate abnormally in the red blood cells of people with dementia. The study included 30 healthy volunteers between the ages of 50 and 69 years who were randomly assigned to receive either 6 mg or 12 mg of astaxanthin or 0 mg placebo per day for 12 weeks. The results revealed that after 12 weeks of treatment, levels of phospholipid hydroperoxides were significantly lower in erythrocytes following astaxanthin supplementation with reductions in the order of about 40 and 50 percent in the 6 and 12 mg groups, respectively, compared with no significant change in the placebo group. These findings suggest that supplementation with astaxanthin improved erythrocyte antioxidant status and decreased phospholipid hydroperoxides levels, which may help prevent dementia.
Astaxanthin Inhibits Tumor Invasion by Decreasing Extracellular Matrix Production and Induces Apoptosis in Experimental Rat Colon Carcinogenesis by Modulating the Expressions of ERK-2, NFkB and COX-2
Invest New Drugs 2011 (Apr); 29 (2): 207–224
AST-treatment decreased the expressions of all these vital proteins, involved in colon carcinogenesis. The ability of AST to induce apoptosis in the colon of DMH-induced rats was confirmed by Annexin-V/PI staining in a confocal microscopy, DNA fragmentation analysis and expression of caspase-3 by Western blotting. In conclusion, astaxanthin exhibits anti-inflammatory and anti-cancer effects by inducing apoptosis in DMH-induced rat colon carcinogenesis by modulating the expressions of NFkB, COX-2, MMPs-2/9, Akt and ERK-2.
Astaxanthin Protects Mitochondrial Redox State and Functional Integrity Against Oxidative Stress
J Nutr Biochem 2010 (May); 21 (5): 381–389
Moreover, AX improved maintenance of a high mitochondrial membrane potential and stimulated respiration. Investigating how AX stimulates and interacts with mitochondria, a redox-sensitive fluorescent protein (roGFP1) was stably expressed in the cytosol and mitochondrial matrix to measure the redox state in the respective compartments. AX at nanomolar concentrations was effective in maintaining mitochondria in a reduced state. Additionally, AX improved the ability of mitochondria to remain in a reduced state under oxidative challenge. Taken together, these results suggest that AX is effective in improving mitochondrial function through retaining mitochondria in the reduced state.
Astaxanthin, a Carotenoid without Vitamin A Activity, Augments Antibody Responses in Cultures Including T-helper Cell Clones and Suboptimal Doses of Antigen
J Nutr 1995 (Oct); 125 (10): 2483–2492
Astaxanthin and beta-carotene may enhance the actions of both Th1 and Th2 cells for humoral immune responses with suboptimal Ag challenges; certain carotenoids may help maintain Ag-mediated immune responses at optimal levels.
Astaxanthin and Canthaxanthin Are Potent Antioxidants in a Membrane Model
Arch Biochem Biophys 1992 (Sep); 297 (2): 291–295
When the conjugated keto-carotenoids, either astaxanthin or canthaxanthin, are added to rat liver microsomes undergoing radical-initiated lipid peroxidation under air, they are as effective as alpha-tocopherol in inhibiting this process. This contrasts with the effect of beta-carotene, which is a much less potent antioxidant when added in this system, without the addition of other antioxidants.
Inhibition of Oxidative Injury of Biological Membranes by Astaxanthin
Physiol Chem Phys Med NMR 1990; 22 (1): 27–38
Carrageenan-induced inflammation of the paw is also significantly inhibited by administration of astaxanthin. These data indicate that astaxanthin functions as a potent antioxidant both in vivo and in vitro.
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