New cytotoxic polyacetylene alcohols from the Egyptian marine sponge Siphonochalina siphonella.

Three new polyacetylenic alcohols, siphonellanols A-C (1-3), together with two known polyacetylenic alcohols (4-5), were isolated from the CHCl₃-soluble fraction of the methanolic extract of the marine sponge Siphonochalina siphonella, collected in Egypt. The structures of 1-3 were determined by spectroscopic analyses of their 1D-, 2D-NMR, and MS spectra and by comparisons with reported data. The cytotoxicity assay revealed that 1-3 exhibited moderate cytotoxic activities against a human cervical cancer cell line (HeLa), a human breast cancer cell line (MCF-7), and a human lung cancer cell line (A549) with IC₅₀ values ranging from 25.9 to 69.2 μM.