Triterpene glycosides from Antarctic sea cucumbers. 1. Structure of liouvillosides A1, A2, A3, B1, and B2 from the sea cucumber Staurocucumis liouvillei: new procedure for separation of highly polar glycoside fractions and taxonomic revision - Antonov, A S; Avilov, S A; Kalinovsky, A I; Anastyuk, S D; Dmitrenok, P S; Evtushenko, E V; Kalinin, V I; Smirnov, A V; Taboada, S; Ballesteros, M; Avila, C; Stonik, V A (J Nat Prod, 2008)