Astaxanthin, a xanthophyll carotenoid, is a secondary metabolite naturally synthesized by a number of bacteria, microalgae, and yeasts. The commercial production of this pigment has traditionally been performed by chemical synthesis, but the microalga Haematococcus pluvialis appears to be the most promising source for its industrial biological production. Due to its collective diverse functions in skin biology, there is mounting evidence that astaxanthin possesses various health benefits and important nutraceutical applications in the field of dermatology. Although still debated, a range of potential mechanisms through which astaxanthin might exert its benefits on skin homeostasis have been proposed, including photoprotective, antioxidant, and anti-inflammatory effects. This review summarizes the available data on the functional role of astaxanthin in skin physiology, outlines potential mechanisms involved in the response to astaxanthin, and highlights the potential clinical implications associated with its consumption.

Protein conformational diseases, such as Alzheimer's, Parkinson's and Huntington's, affect a large portion of aging population. The pathogenic dysfunctional aggregation of proteins in non-native conformations is associated with metabolic derangements and excessive production of reactive oxygen species. Reduction of cellular expression and activity of antioxidant proteins result in increased oxidative stress. Free-radicals derived from mitochondrial dysfunction and from the cyclooxygenase enzyme activity play a role in oxidative damage of brain. Cyclooxygenase also mediates in neuro-inflammation by the production of pro-inflammatory prostaglandins which contribute to brain injury. The pathogenic role of cyclooxygenase has been demonstrated in Alzheimer and Parkinson diseases. The brain responses to detect and control diverse forms of stress are accomplished by a complex network of "longevity assurance processes" integrated to the expression of genes termed vitagenes. Heat shock proteins are a highly conserved system responsible for the preservation and repair of correct protein conformation. Heme oxygenase-1, a inducible and redox-regulated enzyme, is currently considered as having an important role in cellular antioxidant defense. A neuroprotective effect, due to its heme degrading activity, and tissue-specific pro-oxidant effects, due to its products CO and free iron, are under debate. There is a current interest in dietary compounds that can inhibit, retard or reverse the multi-stage pathophysiology of Alzheimer disease, with a chronic inflammatory response, brain injury and beta-amyloid associated pathology. Curcumin and ferulic acid, two powerful antioxidants, the first from the curry spice turmeric and the second a major constituent of fruit and vegetables, have emerged as strong inducers of the heat shock response. Food supplementation with curcumin and ferulic acid is considered a nutritional approach to reduce oxidative damage and amyloid pathology in Alzheimer disease.