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.
Keywords: Cytotoxic; Marine sponge; Polyacetylene; Red Sea; Siphonellanol; Siphonochalina siphonella.