Naphthoquinone pigments from the green sea urchin, Strongylocentrotus droebachiensis

Abstract

Spinochromes are part of a subgroups of quinones called naphthoquinones. These molecules have a series of bioactivity making them a promising target for marine researchers all over the world. Sulphated spinochromes was recently identified, but their structure or bioactivity is yet to be elucidated. In this project, an attempt to extract these sulphated spinochromes from red spherule cells are made. This was done with two different solvents, Milli-Q water, using the principle of hypotonic condition to extract cell content, and Methanol + Trifluoracetic acid which will lyse the cell membrane so that the content leaks out. The extracts were then separated and analysed with UHPLC-DAD-MS. It was determined that none of the extracts contained any of the sulphated spinochromes at the time of the analysis. Due to time restrictions and limited access to an LC-MS system, the data was limited. Therefore, the extracted compounds were identified by available mass but mainly based on their UV/Vis spectra. Spinochrome E, Spinamine E, Spinochrome 502 dimer and spinochrome 536 dimer were identified, as well as the finding of a possible novel PHNQ pigment based on its UV/Vis spectra. Due to limited amount of sample material, the bioactivity tests were limited to antibacterial testing against Bacillus subtilis and ORAC antioxidative assay. The bioactivity assays showed limited antibacterial activity, but antioxidative activity was detected in fractions or close to fractions containing PHNQ pigment according to the UV/Vis spectra. An optimized protocol suggests an improved focus on stability and solubility for further studies of the compounds.