Measurement and interpretation of macular carotenoids in human serum

Thurnham, David I. and Meagher, Katherine A. and Connolly, Eithne and Nolan, John M. (2013) Measurement and interpretation of macular carotenoids in human serum. In: Carotenoids and Retinal Disease :. CRC Press, pp. 187-201. ISBN 9781466502048

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Abstract

The structure and spectral characteristics of nearly 750 carotenoids present in our natural surroundings have been identified. About 50 of these carotenoids are present in the human diet but mostly in small amounts. The major carotenoids in human blood are lutein, β-cryptoxanthin, lycopene, and α-and β-carotene. Their structures are shown in Figure 10.1, and isocratic, reverse-phase chromatography has been shown to separate these carotenoids by many researchers. The carotenoids have at least two major functions in the human body: to provide a source of vitamin A and to act as antioxidants. Of the principal carotenoids in serum, only α-carotene, β-carotene, α-cryptoxanthin, and β-cryptoxanthin are provitamin A carotenoids, that is, they contain at least one β-ionone ring linked to a hydrocarbon chain with a conjugated double bond structure, which can be cleaved by the oxidation of the 15,15′ double bond to form β-apo-15-carotenal. β-apo-15-carotenal is subsequently reduced to retinol. Most carotenoids are not vitamin A precursors. Although many carotenoids possess a β-ionone ring, they contain a variety of substituents that commonly include oxygen. These oxygen-containing carotenoids are known as xanthophylls. A few of these, such as β-cryptoxanthin (Figure 10.1), are vitamin A precursors, but most are not. All carotenoids have antioxidant capacity associated with their conjugated carbon structure. Typically, the longer the polyene chain, the greater the ability of a carotenoid to deactivate reactive oxygen species, such as oxy radicals and singlet oxygen.

Item Type:	Book Section
Additional Information:	Publisher Copyright: © 2014 by Taylor & Francis Group, LLC.
Uncontrolled Keywords:	/dk/atira/pure/subjectarea/asjc/2700
Departments or Groups:
Depositing User:	Admin SSL
Date Deposited:	19 Oct 2022 23:17
Last Modified:	07 Jun 2023 18:40
URI:	http://repository-testing.wit.ie/id/eprint/5163

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