| Summary: | Chemical investigation of the ethanol extract of soft coral <em>Sinularia</em> sp. collected from the South China Sea led to the isolation of three new polyoxygenated sterols, (3<em>S</em>,23<em>R</em>,24<em>S</em>)-ergost-5-ene-3β,23α,25-triol (<strong>1</strong>), (24<em>S</em>)-ergostane-6-acetate-3β,5α,6β,25-tetraol (<strong>2</strong>), (24<em>S</em>)-ergostane-6-acetate-3β,6β,12β,25-tetraol (<strong>3</strong>) together with three known ones (<strong>4</strong>–<strong>6</strong>). The structures, including relative configurations of the new compounds (<strong>1</strong>–<strong>3</strong>), were elucidated by detailed analysis of spectroscopic data (IR, UV, NMR, MS) and by comparison with related reported compounds. The absolute configuration of <strong>1</strong> was further determined by modified Mosher’s method. Compound <strong>5</strong> exhibited moderate cytotoxicity against K562 cell line with an IC<sub>50</sub> value of 3.18 μM, but also displayed strong lethality toward the brine shrimp <em>Artemia salina</em> with a LC<sub>50</sub> value of 0.96 μM.
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