Polar steroid derivatives from the Vietnamese starfish <i>Astropecten polyacanthus</i>

<p>Five polar steroid derivatives, including one new glycosylated polyhydroxysteroid namely polyacanthoside A (<b>1</b>), were isolated from the water-soluble materials from the MeOH extract of the Vietnamese starfish <i>Astropecten polyacanthus</i> using various chromatographic separations. The structure elucidation was confirmed by spectroscopic experiments such as HR-ESI-MS, 1D and 2D NMR. Among the isolated compounds, (20<i>R</i>,24<i>S</i>)-3<i>β</i>,6<i>α</i>,8,15<i>β</i>,24-pentahydroxy-5<i>α</i>-cholestane (<b>3</b>) showed significant cytotoxic effect against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC₅₀ values from 18.03 ± 2.63 to 21.59 ± 3.23 μM.</p