Diversity of Polyhydroxynaphthoquinone Pigments in North Pacific Sea Urchins

Using high‐performance liquid chromatography with diode‐array detection and mass spectrometry ( HPLC ‐ DAD / MS ) we investigated the composition of polyhydroxynaphthoquinone ( PHNQ ) pigments from sea urchins Strongylocentrotus pallidus , St . polyacanthus , St . droebachiensis , Brisaster latifrons and Echinarachnius parma , collected in the Sea of Okhotsk and the Bering Sea. Identification of PHNQ pigments from sea urchins St . polyacanthus , B . latifrons , and E . parma was performed for the first time. Among the usual PHNQ pigments, mono‐ and dimethoxy derivatives of spinochrome E, not previously found in other sea urchins, were discovered in St . polyacanthus and St . droebachiensis . In St . droebachiensis , two monomethoxy derivatives of echinochrome A were detected, isolated previously from only tropical sea urchins. It was found that the composition and total content of pigments of St . droebachiensis depends on the collection area of the sea urchins and its depth and varies from 88 to 331 μg/g of dry shells. Sea urchins St . pallidus , B . latifrons and E . parma had average values for PHNQ pigment content, approximately 30 μg/g, and St . polyacanthus had a low PHNQ content, 13 μg/g.