9,11-Secosteroids and polyhydroxylated steroids from two South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis

•A new 9,11-secosteroid and two new polyhydroxylated steroids were isolated.•Compound 2 had a moderate PTP1B inhibitory activity with IC50 value of 33.05 μM.•Compounds 1–3 showed weak cytotoxicity against K562 and HL-60 cell lines.

A new 9,11-secosteroid, 25(26)-dehydrosarcomilasterol (1), two new polyhydroxylated steroids, 7α-hydroxy-crassarosterol A (2) and 11-acetoxy-7α-hydroxy-crassarosterol A (3), together with three known related ones (4–6), were isolated from the South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis, respectively. The structures of the new steroids were elucidated on the basis of extensive spectroscopic analyses, comparison with the literature data and chemical correlation. Compound 2 exhibited a moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with an IC50 value of 33.05 μM. Compounds 1–3 showed weak in vitro cytotoxicities against the tumor cell lines K562 and HL-60.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide