New Cytotoxic Oxygenated Sterols from the Marine Bryozoan Cryptosula pallasiana

Abstract

Six new sterols (1–6), together with seven known sterols (7–13), were isolated from the CCl₄ extract of the marine bryozoan Cryptosula pallasiana, four (3–6) of which have already been reported as synthetic sterols. This is the first time that these compounds (3–6) are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D) NMR and HR-ESI-MS data. Compounds 1–4, 7 and 10–13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC₅₀ values from 14.73 to 22.11 µg/mL except for compounds 12 and 13.