Crellastatin A: a cytotoxic bis-steroid sulfate from the Vanuatu marine sponge Crella sp

The isolation and structure of crellastatin A, a cytotoxic and nonsymmetric dimeric steroid sulfate present in the Vanuatu Islands marine sponge Crella sp., were investigated. Extensive two-dimensional nuclear magnetic resonance spectroscopy was used for the structural assignment while analysis of ROESY experiments as well as molecular mechanics and dynamics computations were employed to establish the stereochemistry of crellastatin A. Results showed that crellastatin A exhibits in vitro cytotoxic response against human cancer NSCLC-N6 cells.