Non-holostane and holostane triterpene glycosides from spawn of sea cucumber Apostichopus japonicus selenka

Sea cucumber Apostichopus japonicus Selenka, as a traditional tonic, has great edible value and a large-scale aquaculture variety in China. As its spawn has similar nutrients as body wall, residents in many countries often use spawn to make various delicious food, especially Japanese ferment it to make sauce. In this study, four new triterpene glycosides ( 1 - 4 ) together with a known holotoxin B ( 5 ) were obtained from it. New compounds were holotoxin S 1 -S 3 ( 1 - 3 ) with rare 18(16)-lactone ring as well as holotoxin S 4 ( 4 ) with an 18(20)-lactone group belonging to holostane type. Holotoxin B was firstly isolated from spawn of A. japonicus . The structures of four new molecules were elucidated based on extensive spectroscopic analysis and chemical tools. • Four new compounds were obtained in this paper. • Rare lactone ring produced by sea cucumber spawn. • Saponins differ in body wall and spawn. • First report on chemical constituents in sea cucumber spawn.