Ophiocomina nigra

A carotenoid sulfate, ophioxanthin (666), was isolated from the ophiuroid Ophioderma longicaudum from the Mediterranean Sea and shown to be 5,6,5 ,6 -tetrahydro-P,P-carotene-3,4,3 ,4-tetraol 4,4 -disulfate [528]. The carotenoid, dehydroophioxanthin (667) was isolated from the ophiuroid Ophiocomina nigra off Spain and the structure was determined by spectral data analysis [529]. 

Two closely related carotenoid sulphates have been recently isolated from ophiuroids. Ophioxant-hin (266) is the major pigment from both Ophioderma longicaudum (6) and Ophiocomina nigra (183), of which the latter has also furnished dehydroophioxanthin (267), with an acetylenic functionality. 

Biphenyl injected into the starfish Ophiocomina nigra was metabolized primarily to 2-hydroxybiphenyl, with smaller amounts of 4-hydroxybiphenyl and 4,4 -dihydroxybiphenyl being formed (Meyer and Bakke 1977). The percent of total metabolites were, respectively, 78, 14 and 8%. The parent compound was more evident in the seawater than in the tissues of the starfish, viz. seawater 45% biphenyl and 55% metabolites tissues 10% biphenyl and 90% metabolites, i.e. depuration of parent compound was faster than the rate of metabolism and/or depuration of metabolites. 

Ophioxanthin and dehydroophioxanthin were isolated separately or simultaneously from the ophiurians Ophiocomina nigra and Ophioderma longicaudum. Sulfated carotenoids are rare other well-known examples are the bastaxanthins of some sponges of the family lanthellidae (see Chapter 19). 

D Auria, M.V., Minale, L., Ricdo, R., and Uriarte, E. (1991) Dehydroophioxanihin, a new acetylenic carotenoid sulfate from the ophiuroid Ophiocomina nigra. J. Nat. Prod., 54,606-608. 

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