Carotenoids and their metabolism in the goldfish Carassius auratus (Hibuna)

A total of 18 known carotenoids and three new carotenoids, (3S, 4R, 3'S, 6' R)-4-hydroxylutein, (3S, 3'S,'4'R)-4-keto-4'-hydroxydiatoxanthin, and (3S, 3'S, 4'A)-4-keto-4'-hydroxyalloxanthin were isolated from the goldfish Cara ssius auratus. On the basis of structural consideration of the isolated car otenoids and the result of our previously reported feeding experiment of lu tein A and (3R, 3'R)-zeaxanthin to goldfish, the present authors proposed t he possible metabolic pathways from lutein A, lutein B, (3R, 3'R)-zeaxanthi n, diatoxanthin and alloxanthin to fritschiellaxanthin, alpha-doradexanthin , (3S, 3'S)-astaxanthin: (3S, 3'S)-7,8-didehydroastaxanthin, and (3S, 3'S)- 7,8,7',8'-tetradehydroastaxanthin, respectively. (C) 1999 Elsevier Science Inc. All rights reserved.