Since the first structural elucidation of β-carotene by Kuhn and Karrer in 1930, about 750 naturally occurring carotenoids had been reported till 2004. Improvements of analytical instruments such as NMR, MS, HPLC, etc., have made it possible to perform the structural elucidation of very minor carotenoids in nature. Annually, new structural carotenoids are being reported in nature. The present paper provides a review of experimental techniques for structural elucidation and analysis of natural carotenoids including extraction, isolation, chemical derivatization methods and HPLC, UV-VIS, MS, NMR, CD spectrometry.

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Dietary carotenoids have attracted much attention because of their antioxidant activities and other biological activities including anti-cancer, anti-allergic, and anti-obese actions. Although no less than forty carotenoids are ingested under usual dietary habits, only several carotenoids and their possible metabolites have been found in human tissues. Little is known about the mechanism underlying the preferential accumulation of these carotenoids. Recently, facilitated diffusion mediated by scavenger receptor class B type 1 in addition to simple diffusion has been reported to mediate the intestinal absorption of carotenoids in mammals. Specificity of the receptor for carotenoids might cause selective absorption in intestine. The metabolism after intestinal absorption of carotenoids also affects their accumulation in tissues. This paper reviews the absorption and metabolism of carotenoids by introducing recent advances in this field.

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Obesity, which results from an imbalance between energy intake and energy expenditure, becomes a major health risk factor, causing numerous and various diseases such as diabetes, hypertension, and cardiovascular diseases. Recently, a specific component in brown algae has garnered much attention for its anti-obesity and anti-diabetic effects attributable to a unique mechanism. Fucoxanthin, a carotenoid found in brown algae such as Undaria pinnatifida and Sargassum fulvellum, induces uncoupling protein 1 (UCP1) expression in white adipose tissue (WAT). UCP1 is an inner membrane mitochondrial protein that can dissipate energy through oxidation of fatty acids and heat production. Furthermore, fucoxanthin improves insulin resistance and ameliorates blood glucose levels through down-regulation of adipocytokines related to insulin resistance in WAT and up-regulation of glucose transporter 4 (GLUT4) in skeletal muscle. Fucoxanthin is a beneficial compound for the prevention of the metabolic syndrome.

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Carotenoids have been demonstrated to possess various effects on human health. However, there is no report about the effects of carotenoids on degranulation of mast cell that is critical for type I allergy. We recently found the inhibitory effect of carotenoids on antigen-induced degranulation of mast cells. Fucoxanthin, astaxanthin, zeaxanthin and β-carotene inhibited antigen-induced aggregation and translocation of high affinity IgE receptor (FcεRI) to lipid rafts which are known as platforms. It is interesting to verify the relationship between the multiple bioactive effects of carotenoids and modulation of lipid rafts’ function.

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Antioxidant micronutrients, such as vitamins and carotenoids, exist in abundance in fruits and vegetables and have been known to contribute to the body’s defense against reactive oxygen species. Recent numerous epidemiologic studies have demonstrated that a high dietary consumption of fruit and vegetables rich in carotenoids or with high serum carotenoid concentrations results in lower risks of certain cancers, diabetes, and cardiovascular disease. These epidemiologic studies have suggested that antioxidant carotenoids may have a protective effect against several lifestyle-related diseases. Beta-cryptoxanthin is a carotenoid pigment found especially in Japanese mandarin (Citrus unshiu Marc.) fruit, which is mainly produced in Japan. Our nutritional epidemiologic survey, Mikkabi Study, utilized data derived from health examination of inhabitants performed in the town of Mikkabi in Shizuoka, Japan. In this survey, we have measured serum beta-cryptoxanthin as a specific bio-marker to estimate the consumption of Japanese mandarin fruit. From the cross-sectional analyses from the Mikkabi Study, we found the inverse associations of serum β-cryptoxanthin with the risks for atherosclerosis, insulin resistance, liver dysfunctions, metabolic syndrome, low bone mineral density, and oxidative stress.
In this chapter, recent epidemiologic studies about the associations between serum beta-cryptoxanthin with the risk for several lifestyle-related diseases were reviewed.

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Astaxantin is a naturally occurred orange-red pigment in a wide variety of living organisms such as microalgae, yeast, salmon, trout, crayfish and crustaceans. Classically astaxanthin have been commercially used as feed additives to improve the pigmentation in aquaculture and poultry industries. In addition to its role as a pigment, astaxanthin may efficiently work biological antioxidant in vivo. Recently it has been reported its potent biological actions, such as antioxidative activity, anti-diabetic, anti-inflammatory actions, immunomodulatory and anticancer activity. Thus, in the1990s, there has been significant commercial interest in developing cultivation of unicellular green algae named Haematococcus as a promised source of astaxanthin used for food industry. The aim of this review, a summary of industrial production of astaxanthin by Heamatococcus algae and the potent biological activity of astaxanthin, was to provide a further understanding of the beneficial health effects of astaxanthin.

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