Chemotaxonomic study of the most abundant Egyptian sea-cucumbers using ultra-performance liquid chromatography (UPLC) coupled to high-resolution mass spectrometry (HRMS)

Actinopyga mauritiana, Bohadschia marmorata, Holothuria leucospilota, H. edulis, H. atra and H. polii are the abundant sea-cucumbers inhabiting either Red or Mediterranean Sea shore in Egypt. The aim of this study was to elucidate the metabolic content in the tegument of the selected sea-cucumbers using ultra-performance liquid chromatography coupled to high-resolution mass spectrometry (UPLC/HRMS). The identified metabolites included sulfated saponins such as holothurin B1 and 24-dehydroechinoside A and non-sulfated saponins such as bivittoside C and D. Our results showed that B. marmorata is substantially different from all the other species and occupies alone one taxon. Consequently, it can be suggested to reclassify the family Holothuriidae into three subfamilies. The first suggested comprising the genera, Holothuria and Actinopyga, the second includes only genus Bohadschia, whereas the third includes only genus Pearsonothuria. Lipidomic analysis of sea-cucumbers showed high variation in saturated and unsaturated fatty acids (USFAs) between the collected species. H. edulis and B. marmorata showed the highest amount of all identified SFAs. Among the USFAs, palmitoleic, docosatrienoic and linoleic acid were detected in varied amount in most species.