A series of carotenoids with 19- or 19'-hexanoyloxy moieties, 19'-hexanoyloxyfucoxanthin (1), 19'-hexanoyloxyfucoxanthinol (2), 19'-hexanoyloxyhalocynthiaxanthin (3), 19-hexanoyloxycrassostreaxanthin A (4), 19-hexanoyloxymytiloxanthin (5), and 19-hexanoyloxyallenicmytiloxanthin (6) were isolated from the edible part of the sea mussel, Mytilus galloprovincialis, grown in the Black Sea, Ukraine. Among them, 3, 4, and 6 were new compounds. These structures were charcterized by UV-vis, fast atom bombardment mass spectrometry, circular dichroism, and (1)H NMR spectroscopic data. They were assumed to be metabolites of 19'-hexanoyloxyfucoxanthin (1).

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The composition and content of carotenoids were studied in the body of Black sea gastropod Rapana venosa. The methods of thin layer and high performance liquid chromatography, mass-spectra and the spectra in UV-VIS diapason were used for isolation and identification of compounds belonging to this group. 84-87% of carotenoids were identified. The main part of them is presented by mytiloxanthin-28-30%. Other-pectenolon, diatoxanthin, alloxanthin-composed 10-15% of total content, with exception of β-carotene-3-4%. The fraction containing complex esters of pectenolon, diatoxanthin, alloxanthin and mytiloxanthin was also isolated. It composes 17-20% of the pigments of carotene row. The minor components were not determined. Study discusses the pathways of carotenoid metabolic transformation in the R. venosa tissues studying trophic system "mollusc-filter-mollusc-predator" on examples of Mytilus galloprovincialis and R. venosa.

This work deals with studies on the content of carotenoids, the state of antioxidant (AO) enzymatic complex, and the intensity of lipid peroxidation in tissues (hepatopancreas, gill, and foot) of the Black Sea bivalve mollusc Anadara inaequivalvis. Tissues with a high content of the pigment have been established to have a low activity of the key AO enzymes: superoxide dismutase, catalase, and glutathione reductase, as well as an elevated content of reduced glutathione (R 2 = 0.81-0.97). The differences of the recorded activities between the tissues reached 1.7-2.9 times ( p < 0.05-0.01). At increased concentrations (more than 2.5 mg • 100 g -1 tissue), carotenoids show an insignificant pro-oxidant effect manifested in a rise of glutathione peroxidase activity. The competitive interrelations between these molecular complexes for the same kinds of reactive oxygen species (O 2 , OH • , and 1 O 2 ) are discussed.