Characterizing gangliosides in six sea cucumber species by HILIC-ESI-MS/MS

An HILIC-ESI-MS/MS method was established to analyze ganglioside (GLS) in sea cucumbers. In total, 17 GLS subclasses were detected in six sea cucumber species. The basic sea cucumber GLSs (SC-GLSs) were elucidated as NeuGc2-6Glc1-1Cer (SC-GM₄). The polymerization degree of the sialic acid (Sia) of SC-GLSs can be up to 4, and the linkage among Sias was mostly determined to be 2-8 or 2-11. Neu5Gc, sulfated and fucosylated NeuGc prevalently existed in SC-GLSs. Moreover, a new SC-GLSs structure with phosphoinositidyled Sia was first observed in Bohadschia marmorata. For the first time, we demonstrated that the content of SC-GD₄, which is the dominant GLS in sea cucumbers, was 27-67%. Minor GLSs characterized as SC-GT₂(Neu5GcMe) and SC-GQ₂(Neu5GcMe) were also discovered. Additionally, SC-GD₄ and SC-GD₄(1S) could significantly promote the differentiation of PC12 cells with structure-selectivity (p < 0.05). Our results provide insights into SC-GLSs to elucidate their Sia substituent and core saccharide chain linkage.