Extraction, structural characterization and antioxidant activity of polyhydroxylated 1,4-naphthoquinone pigments from spines of sea urchin Glyptocidaris crenularis and Strongylocentrotus intermedius

In the present study, the effects of operational parameters on adsorption and desorption capacity of polyhydroxylated 1,4-naphthoquinone (PHNQ) pigments on macroporous resin in static mode were evaluated. On this basis, a suitable operating condition was selected which recovered 83.96 ± 0.71 and 80.58 ± 1.48 % of PHNQ pigments from Glyptocidaris crenularis and Strongylocentrotus intermedius spines, respectively. Based on accurate molecular mass and ultraviolet–visible (UV–Vis) spectral data acquired by ultra-performance liquid chromatography hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer (UPLC Q-TOFMS), spinochrome E, spinochrome D and spinochrome B were tentatively identified in the pigment extract prepared from G. crenularis. In contrast, only spinochrome B was identified in the pigment extract from S. intermedius. Between the two extracts, the one from G. crenularis showed stronger DPPH radical scavenging ability and ferrous ion chelating capacity. In our opinion, the different PHNQ compounds existing in the two extracts resulted in the difference in antioxidant activity.