Rapid Profiling of Saponin Extracts from Stichopus horrens Sea Cucumbers by Mass Spectrometry

Sea cucumbers produce bioactive compounds known as saponins. Structurally, these triterpene glycosides contain different sugar moieties that are attached to a lanostane-based aglycone backbone. This study aims to rapidly profile the saponins of the Philippine sea cucumber, Stichopus cf. horrens, by mass spectrometry (MS). MS and tandem MS (MS/MS) were acquired using a UPLC-QToF (ultra-performance liquid chromatography–quadrupole time-of-flight) mass spectrometer. The aglycone and glycan components of the saponins were determined from the corresponding MS2 spectra. A total of 22 saponins were detected, nine of which were similar to known sea cucumber saponins. Some of these saponins – such as holothurinoside C, holothurinoside H, impatienoside A, and stichloroside A2/B2 – have been shown to be effective as antitumor, anti-cancer, or antifungal compounds. The other 13 saponins we detected appear to be unique as these have not been previously reported. Glycan and potential aglycone components of the new saponins based on MS/MS are proposed. The methods used in this study may be used to rapidly profile saponin compounds in sea cucumbers and quickly identify bioactive compounds or new saponins that may be of interest.