A Holothurian Triterpene Glycoside Holothurin A2 (= Echinoside A) Isolated From the Starfish Choriaster granulatus

A triterpene glycoside identified as holothurin A2 (= echinoside A) was isolated from the extract of the tropical starfish Choriaster granulatus and identified by extensive nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization (ESI) mass spectrometry techniques. The fact of obtaining this typical for tropical sea cucumbers metabolite in starfish may be explained by feeding of C. granulatus on sea cucumbers of the family Holothuriidae that allows to use triterpene glycosides as food source markers in predators of sea cucumbers