A Novel Carotenoid with a Unique 2,6-Cyclo-?-End Group, Roretziaxanthin, from the Sea Squirt Halocynthia roretzi

A novel carotenoid with a unique 2,6-cyclo-psi-end group, named roretziaxanthin (1), was isolated from the sea squirt Halocynthia roretzi as a minor carotenoid along with (3S,3'S)-astaxanthin, alloxanthin, halocynthiaxanthin, mytiloxanthin, mytiloxanthinone, etc. This structure was determined to be 3-hydroxy-1',16'-didehydro-1',2'-dihydro-2',6'-cyclo-beta,psi-carotene-4,4'-dione by UV-VIS, MS, and NMR spectral data. The formation mechanism of roretziaxanthin in the sea squirt was discussed.

Automated summary

A novel carotenoid with a unique 2,6-cyclo-psi-end group, named roretziaxanthin (1), was isolated from the sea squirt Halocynthia roretzi as a minor carotenoid. Its structure was determined using UV-VIS, MS, and NMR spectral data, and the formation mechanism in the sea squirt was discussed.