Bioactive polyhydroxylated sterols from the marine sponge Haliclona crassiloba

•Four new polyhydroxylated sterols were isolated from the sponge Haliclona crassiloba.•This is the first report of a steroid profile for this species.•Compounds 1 and 2 represented rare examples of Δ17(20) steroids.•Structures were established by spectroscopic methods and comparisons with literature values.•Two compounds showed moderate activity against some of the Gram-positive strains.

Four new polyhydroxylated sterols, named halicrasterols A–D (1–4), together with six known analogs (5–10) were isolated from the marine sponge Haliclona crassiloba. Compounds 1 and 2 represented rare examples of steroids featuring 17(20)E-double bonds. The structures of 1–10 were elucidated by spectroscopic analysis and comparison with reported data. This is the first report of a steroid profile for this species. The antimicrobial activities of 1–10 were evaluated against a panel of bacterial and fungal strains in vitro, and compounds 4 and 9 showed moderate activity against some of the Gram-positive strains with MICs ranging from 4 to 32 μg/mL.

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