Salmoxanthin, deepoxysalmoxanthin, and 7,8-didehydrodeepoxysalmoxanthin from the Salmon Oncorhynchus keta.

The absolute configuration of salmoxanthin (5,6-epoxy-5,6-dihydro-beta,epsilon-carotene-3,3',6'-triol) (1) first isolated from the salmon Oncorhynchus keta was determined to be 3S, 5R, 6S, 3'S, 6'R. Furthermore, two minor carotenoids, deepoxysalmoxanthin (2) and 7,8-didehydrodeepoxysalmoxanthin (3), were isolated, and their structures were determined to be (3R,3'S,6'R)-beta,epsilon-carotene-3,3',6'-triol and (3R,3'S,6'R)-7,8-didehydro-beta,epsilon-carotene-3,3',6'-triol by (1)H NMR and CD spectroscopy.