A new sterol from the Vietnamese marine sponge Xestospongia testudinaria and its biological activities

A new sterol, langcosterol A (1), together with two known sterols 2 and 3, were isolated from the marine sponge Xestospongia testudinaria collected in Vietnam. Their chemical structures were elucidated on the basis of extensive spectroscopic analyses and comparisons with published data. The new compound 1 and the known compound 3 exhibited moderate cytotoxic activities against three human cancer cell lines (A549, lung cancer; MCF7, breast cancer; HeLa, cervical cancer) and a human normal cell line (WI-38 fibroblast), with IC50 values ranging from 29.0 to 68.0 mu M. [GRAPHICS] .