3<i>-epi</i>-Aplykurodinone B, a New Degraded Sterol from <i>Aplysia fasciata</i>

Abstract

The anaspidean mollusk Aplysia fasciata from Río San Pedro (Cádiz, Spain) contains the known degraded sterols aplykurodinone B (2) and aplykurodin B (4) together with the new 3-epi-aplykurodinone B (5). The structure of 5 was elucidated by interpretation of spectral data, and its relative stereochemistry was established using NOEDS experiments. The new compound 5 exhibited cytotoxicity against four tumor cell lines.