Triterpene tetraglycosides from the sea cucumber <i>Stichopus horrens</i>

<p>Using various chromatographic separations, three triterpene tetraglycosides (<b>1–3</b>), including one new compound, namely stichorrenoside E (<b>1</b>) along with thelenotoside B (<b>2</b>) and deacetyl thelenotoside B (<b>3</b>), were isolated from the MeOH extract of the Vietnamese sea cucumber <i>Stichopus horrens</i>. Their structures were confirmed by spectroscopic experiments, such as 1D and 2D NMR and HR-ESI-MS. Deacetylated thelenotoside B (<b>3</b>) is firstly isolated as a natural product. Among these compounds, thelenotoside B (<b>2</b>) showed strong cytotoxicities against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC<sub>50</sub> values from 0.95 ± 0.08 to 1.90 ± 0.13 μM, whereas stichorrenoside E (<b>1</b>) and deacetyl thelenotoside B (<b>3</b>) exhibited significant activities with the IC<sub>50</sub> values from 6.87 ± 0.25 to 11.62 ± 1.05 μM.</p>