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

• An HILIC-HRMS method was established to analyze sea cucumber gangliosides (SC-GLSs). • Neu5Gc, sulfated and fucosylated Neu5Gc were prevalently found in SC-GLSs. • Phosphoinositidyled GLSs were identified in SC-GLSs for the first time. • GD 4 and GD 4 (1S) were the dominant gangliosides in sea cucumbers. • SC-GLSs could structure-selectively promote the differentiation of PC12 cells. 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-GM 4). 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-GD 4 , which is the dominant GLS in sea cucumbers, was 27–67%. Minor GLSs characterized as SC-GT 2 (Neu5GcMe) and SC-GQ 2 (Neu5GcMe) were also discovered. Additionally, SC-GD 4 and SC-GD 4 (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. [ABSTRACT FROM AUTHOR]