Metabolism of carotenoids in salmonids. Part 2. Distribution and absolute configuration of idoxanthin in various organs and tissues of one atlantic salmon ( Salmo salar, L.) fed with astaxanthin

• Published in: Helvetica Chimica Acta
• Main Authors: Schiedt, Katharina, Mayer, Hans, Vecchi, Max, Glinz, Ernst, Storebakken, Trond
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1988
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1002/hlca.19880710425; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fhlca.19880710425; https://onlinelibrary.wiley.com/doi/pdf/10.1002/hlca.19880710425

Abstract The content of total carotenoids and the ratio astaxanthin/idoxanthin ( = 3,3′‐dihydroxy‐β,β‐carotene‐4,4′‐dione/3,3′,4′‐trihydroxy‐β,β‐caroten‐4‐one) in varoius organs and tissues of one Atlantic salmon ( Salmo salar , L.) reared indoors in a tank were analyzed after feeding ‘racemic’ ((3 R ,3′ R )/(3 R ,3′ S; meso )/(3 S ,3′ S ) 1:2:) astaxanthin (90 mg/kg feed) during one yera. Configurational analysis of astaxanthin was carried out via the (−)‐dicamphanate derivative and that of idoxanthin after reaction with (+)‐( S )‐l‐(l‐naphthyl)ethyl isocyanate. Separation of all eight optical isomers of idoxanthin‐tricarbamate derivatives by HPLC is described. In salmon, enzymatic reduction of astaxanthin was found to be sterospecific leading to th (4′ R )‐hydroxy group irrespective of the configuration at C(3′), thus resulting in four different stereoisomers of idoxanthin formed from (3 R ,3′ R ), (3 R ,3′ S meso )‐, and (3 S 3′ S )‐astaxanthin present in the diet.