Canthaxanthines

Fig. 3. Commeicially important carotenoids P-caiotene (10), canthaxanthin [514-78-3] (11), astaxanthin [472-61-7] (12), P-apo-8 -caiotenal [1107-26-2] (13), P-apo-8 -caiotenoic acid ethyl ester [1109-11-1] (14), and citranaxanthin [3604-90-8] (15).

Canthaxanthin. The newest of the synthetically produced carotenoid color additives, canthaxanthin [514-78-3] (39) (P-carotene-4-4 -dione), became commercially available about 1969 (60). Its Cl designation is Food Orange 8, Cl No. 40850. Its EEC designation is E 160g. 

Unknown until 1950 when E. Haxo isolated it from an edible mushroom Cantharellus cinnabarinus canthaxanthin has since been identified in sea trout, algae, daphnia, salmon, brine shrimp, and several species of flamingo. Crystalline canthaxanthin is prepared synthetically from acetone or P-ionone using procedures similar to those used for -carotene and P-apo-8 -carotenal (55). 

Canthaxanthin crystallines from various solvents as brownish violet, shiny leaves that melt with decomposition at 210°C. As is the case with carotenoids in general, the crystals are sensitive to light and oxygen and, when heated in solution or exposed to ultraviolet light or iodine, form a mixture of cis and trans stereoisomers. Consequentiy, crystalline canthaxanthin should be stored under inert gas at low temperatures. Unlike the carotenoid colorants P-carotene and P-apo-8 -carotenal, canthaxanthin has no vitamin A activity. It is chemically stable at pH 2—8 (the range normally encountered in foods) and unaffected by heat in systems with a minimal oxygen content. 

The solubility of canthaxanthin in most solvents is low compared with P-carotene and P-apo-8 -carotenal. Oil solutions of canthaxanthin are red at all concentrations. Aqueous dispersions are orange or red depending on the type of emulsion prepared. 

O. Isler, R. Ruegg, and P. Schudel, Chimia 15, 208—226 (1961). Includes a discussion of P-carotene, P-apo-8 -carotenal, and canthaxanthin from the standpokit of preparation, toxicity, analysis, and appHcation. 

R. H. Bunnell and B. Borensteki, Food Technol 21, 13A—16A (1967). A brief review of the history, natural occurrence, properties, market forms, and stabkity of canthaxanthin. 

Although the carotenoids can be obtained from natural sources, it is far more economical to manufacture them for commercial use (130). Three have been manufactured for many years -carotene [7235-40-7] (42), canthaxanthin [514-78-3] (43), and P-apo-8 -carotenal [1107-26-2] (44) (131). Their stmctures are shown ia Figure 1. 

Fig. 1. Carotenoid pigments -carotene (42), P-apo-8 -carotenal (44), and canthaxanthin (43) = structure (42) with ketone groups at the 4 and 4 positions.

Durch Reduktion von Canthaxanthin (4,4 -Diketo-/ -carotin) an Quecksilber ist die Herstellung des 5,5, 6,6 -Tetrahydro-carotins in hoher Ausbeute moglich3 ... 

Das Carotinoid Canthaxanthin bildet bei -1,55 V (vs. Ag-Draht) an Quecksilber das, Retro-diacetat 7 ... 

C22H32O3 15353-43-2) see Canthaxanthin (4-acetoxyretinyl)triphenylphosphonium chloride (04( 490102 15353-45-4) see Canthaxanthin 6-acetoxy-2,5,7,8-tctramethyl-2-(4-nitrophenoxymethyl>-4-chromanone... 

C gH, P 603-35-0) see Acrivastine Betacarotene Calcipotriol Canthaxanthin Cefixime cis-Cefprozil Etretinate llopfost Imiquimod Isotretinoin Repaglinide Retinol Tretinoin... 

GRADELET S, ASTORG P, LECLERC J, CHEVALIER J, VERNEVAUT M F and SIESS M H (1996) Effects of canthaxanthin, lycopene and lutein on liver xenobiotic metabolising enzymes in the Tat. Xenobiotica 26(1) 49-63. 

LOTAN T and HIRSCHBERG J (1995) Cloning and expression in E. coli of the gene encoding 3-C-4-oxygenase, that converts (3-carotene to the ketocarotenoid canthaxanthin in Haematococcus pluvialis , FEBS Lett, 364, 125-8. 

There are basically two types of carotenoids those that contain one or more oxygen atoms are known as xanthophylls those that contain hydrocarbons are known as carotenes. Common oxygen substituents are the hydroxy (as in p-cryptoxanthin), keto (as in canthaxanthin), epoxy (as in violaxanthin), and aldehyde (as in p-citraurin) groups. Both types of carotenoids may be acyclic (no ring, e.g., lycopene), monocyclic (one ring, e.g., y-carotene), or dicyclic (two rings, e.g., a- and p-carotene). In nature, carotenoids exist primarily in the more stable all-trans (or all-E) forms, but small amounts of cis (or Z) isomers do occur. - ... 

It has been established that carotenoid structure has a great influence in its antioxidant activity for example, canthaxanthin and astaxanthin show better antioxidant activities than 3-carotene or zeaxanthin. 3- 3 3-Carotene also showed prooxidant activity in oil-in-water emulsions evaluated by the formation of lipid hydroperoxides, hexanal, or 2-heptenal the activity was reverted with a- and y-tocopherol. Carotenoid antioxidant activity against radicals has been established. In order of decreasing activity, the results are lycopene > 3-cryptoxanthin > lutein = zeaxanthin > a-carotene > echineone > canthaxanthin = astaxanthin. ... 

It is assumed that in order to have vitamin A activity a molecule must have essentially one-half of its structure similar to that of (i-carotene with an added molecule of water at the end of the lateral polyene chain. Thus, P-carotene is a potent provitamin A to which 100% activity is assigned. An unsubstituted p ring with a Cii polyene chain is the minimum requirement for vitamin A activity. y-Car-otene, a-carotene, P-cryptoxanthin, a-cryptoxanthin, and P-carotene-5,6-epoxide aU have single unsubstimted rings. Recently it has been shown that astaxanthin can be converted to zeaxanthin in trout if the fish has sufficient vitamin A. Vitiated astaxanthin was converted to retinol in strips of duodenum or inverted sacks of trout intestines. Astaxanthin, canthaxanthin, and zeaxanthin can be converted to vitamin A and A2 in guppies. ... 

Carotenoid oxidation products were not only formed from the parent molecules in order to elucidate structure, they were also obtained by partial or total synthesis or by direct oxidation of carotenoid precursors. Thus, apo-8 -lycopenal was synthesized in 1966 more recently, the ozonide of canthaxanthin was obtained by chemical oxidation of canthaxanthin. ... 

Zurcher, M. and Pfander, H., Oxidation of carotenoids II. Ozonides as products of the oxidation of canthaxanthin, Tetrahedron, 55, 2307, 1999. 

Zeaxanthin, lutein short-chain diesters and intermediates for canthaxanthin and astaxanthin synthesis... 

Gradelet, S. et al., Effects of canthaxanthin, astaxanthin, lycopene and lutein on Ever xenobiotic-metabolizing enzymes in the rat, Xenobiotica, 26, 49, 1996. 

Tanaka, T. et al., Suppression of azoxymethane-induced rat colon carcinogenesis by dietary administration of naturally occurring xanthophylls astaxanthin and canthaxanthin during the post-initiation phase, Carcinogenesis, 16, 2957, 1995. 

Choubert, G. and Heinrich, O., Carotenoid pigments of green alga Haematococcus pluvialis assay on rainbow trout Oncorhynchus mykiss, pigmentation in comparison with synthetic astaxanthin and canthaxanthin. Aquaculture, 112, 217, 1993. 

Astaxanthin, capsanthin, lutein, zeaxanthin, canthaxanthin, P-cryptoxanthin, echinenone, 15-cis-P-carotene, 13-cis- P-carotene, a-carotene, all-ircms P-carotene, 9-cis-P-carotene, 5-carotene, lycopene... 

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