Chemical structure lutein

FIGURE 13.2 Chemical formulas of macular xanthophylls. It can be noted that the chemical structures of (meso)-zeaxanthin and lutein differ only by the position of a single double bond. 

The success of the carotenoid extracts led to the commercialization of synthetic carotenoids, some with the same chemical structure as those in the plant extracts and others with modifications to improve their technological properties. The yellow beta-carotene was synthesized in 1950, followed by the orange beta-8-carotenal in 1962 and the red canthaxanthin in 1964. A number of others soon followed, methyl and ethyl esters of carotenoic acid, citraxanthin, zeaxanthin, astaxanthin, and recently lutein. 

Fig. I. Chemical structures of carotenoids, the dependence ofthe ground-state properties on their m-tra/ij configurations being described in Sec. II, (a) p-Carotene, (b) canthaxanthin, (c) zeaxanthin, (d) lutein, (e) /3-apo-8 -carotenal, (f) lycopene, (g) neurosporene, (h) spheroidene, (i) spirilloxanthin and (j) okenone. For each carotenoid, the number of conjugated C=C plus C=0 bonds is shown.

Figure 8.4 Chemical structures of common carotenoids important to animal-based food products. A = p-carotene B = zeaxanthin C = lutein D = canthaxanthin E = astaxanthin.

Lutein 11 and its derivatives are found only in Rhodophyta (macrophytic type), Cryptophyta, Euglenophyta, Chlorarachniophyta, and Chlorophyta (Table 106.2), but nothing is known about cx-carotene 10 hydroxylation. The chemical structures of siphonaxanthin 63 [66], loroxanthin 62, prasinoxanthin 61, and monadoxanthin 59 suggest that they are derived from lutein, but the pathways and enzymes remain unknown (Fig. 106.3) [6]. 

Figure 1. Chemical structure of some common carotenoids. Abbreviations A, 3-carotene B, a-carotene C, lycopene D, lutein E, zeaxanthin E, P-cryptoxanthin.

Fig. 5.3. Chemical structure of chlorophyll a (note the long phytyl side chain) and skeleton formulae of 8-carotene and the carotenol lutein.

Carotenoids are a class of lipophilic compounds with a polyisoprenoid structure. Most carotenoids contain a series of conjugated double bonds, which are sensitive to oxidative modification and cis-trans isomerization. There are six major carotenoids (ji-carotenc, a-carotene, lycopene, P-cryptoxanthin, lutein, and zeaxanthin) that can be routinely found in human plasma and tissues. Among them, p-carotene has been the most extensively studied. More recently, lycopene has attracted considerable attention due to its association with a decreased risk of certain chronic diseases, including cancers. Considerable efforts have been expended in order to identify its biological and physiochemical properties. Relative to P-carotene, lycopene has the same molecular mass and chemical formula, yet lycopene is an open-polyene chain lacking the P-ionone ring structure. While the metabolism of P-carotene has been extensively studied, the metabolism of lycopene remains poorly understood. 

Lakshminarayana, R. Aruna, G. Sangeetha, R.K. Bhaskar, N. Divakar, S. Baskaran, V. 2008. Possible degradation/bioSansformation of lutein in vitro and in vivo Isolation and structural elucidation of lutein metabolites by HPLC and LC-MS (atmospheric pressure chemical ionization). Free Radic. Biol. Med. 45 982-993. 

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