Seasonal and taxa impact on edible sea cucumber metabolome as analyzed via a multiplex approach of mass spectroscopy-based metabolomics

Sea cucumbers, belonging to class Holothuroidea, are marine invertebrates with substantial bioactive compounds and nutritive value. This study presents a multiplex metabolomics approach to dissect between winter and summer samples of two Red Sea cucumbers: Holothuria atra and Actinopyga crassa. LC-MS and GC-MS followed by multivariate data analyses were employed for metabolites profiling and seasonal biomarkers assignment for each species. A total of 314 metabolites were annotated in both species belonging to amino acids, sugars, sugar alcohols, acids, triacylglycerides (TAGs), phospholipids, lyso-phospholipids, sphingolipids, phosphatidylcholines, diacylglycerols, different glycolipids, and others, adding to the nutritive value of sea cucumber. GC-MS analysis revealed for amino acids i.e., alanine as the main polar primary metabolite class in sea cucumbers. LC-MS analysis targeting non-polar metabolites revealed TAGs as the main class followed by phospholipids and lysophospholipids. Multivariate orthogonal partial least square discriminant analysis (OPLS-DA) revealed that A. crassa is enriched in alanine and lactic acid than H. atra versus higher levels of pyroglutamic acid and ethanolamine and TAGs in the later. Summer A. crassa was distinguished from its winter specimen by its higher TAGs, glycine and glycerol levels versus enrichment of winter samples in lyso-phospholipids, isoleucine, and proline. Such metabolomic study revealed for A. crassa and H. atra richness in nutrient metabolites, alongside collection season effect on their amino acids and lipids profiles.