Diets high in antioxidants may help to reduce oxidative stress in the nervous system and may reduce the risk of neurodegenerative diseases such as Alzheimer and Parkinson disease. Astaxanthin is such antioxidant which has been intensively studied for its neuroprotective activity.
Lee and co-workers at the University of Pittsburgh, USA, concluded in their study that astaxanthin may provide a valuable therapeutic strategy for the treatment of progressive neurodegenerative disease such as Parkinson disease [1]. The scientists tested the protective role of astaxanthin against neurotoxin-induced apoptosis of the substantia nigra neurons in the mouse model of Parkinson's disease. As neurotoxin they used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine which is widely used in study disease models in various animal studies and acts by destroying dopaminergic neurons in the substantia nigra of the brain. They also investigated the effect of the phytochemical on 1-methyl-4-phenylpyridinium-induced cytotoxicity in human neuroblastoma cells. Their results show that the protective effects of astaxanthin are the results of its strong antioxidant activity and its stimulation of the expression of superoxide dismutase and catalase.
One year earlier, Lee published the results of a study in the Journal of Clinical Biochemistry and Nutrition about the neuroprotective effects of astaxanthin against oxidative stress by cerebral ischemia [2]. The phytochemical, dosed at 30 mg/kg, showed a neuroprotective efficacy 60% compared with the control group. Astaxanthin surpressed the expression of regulation inducible nitric oxide synthase. The study concluded that the neuroprotective effects of astaxanthin were related to anti-oxidant activities in global ischemia.
A study by Korean researchers, lead by Kim, concluded that pre-treatment with astaxanthin inhibited H2O2-mediated apoptotic death of mouse neural progenitor cells via modulation of p38 and MEK signaling pathways [3]. They pre-treated the cells with astaxanthin for 8 h prior to a treatment with H2O2 and found that astaxanthin significantly inhibited apoptosis and induced cell growth in a dose-dependent manner. A Japanese study conducted at the Nagoya University also found that a pre-treatment with astaxanthin protected human neuroblastoma SH-SY5Y cells against neurotoxins [4]. Neuroblastoma SH-SY5Y cell line is used as in vitro model of dopaminergic neurons for Parkinson disease research. The Japanese researchers explored the neuroprotective effects of astaxanthin using an oxidative stress-induced neuronal cell damage system. Treatment of the cells with the neurotoxins DHA hydroperoxide or 6-hydroxydopamine (both produce reactive oxygen species in eurons) resulted in lower cell viability. Pre-treatment with the phytochemical significantly inhibited production of intracellular reactive oxygen species. They concluded that astaxanthin may reduce oxidative stress-associated neurodegeneration and could be a potential candidate for natural brain food.
[1]Astaxanthin protects against MPTP/MPP+-induced mitochondrial dysfunction and ROS production in vivo and in vitro. Food Chem Toxicol. 2011 Jan;49(1):271-80.
[2] Neuroprotective Effects of Astaxanthin in Oxygen-Glucose Deprivation in SH-SY5Y Cells and Global Cerebral Ischemia in Rat. J Clin Biochem Nutr. 2010 Sep;47(2):121-9.
[3] Astaxanthin inhibits H2O2-mediated apoptotic cell death in mouse neural progenitor cells via modulation of P38 and MEK signaling pathways. J Microbiol Biotechnol. 2009 Nov;19(11):1355-63.
[4] Astaxanthin protects neuronal cells against oxidative damage and is a potent candidate for brain food. Forum Nutr. 2009;61:129-35.
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