Isolation and structural elucidation of the crellastatins I-M: cytotoxic bis-steroid derivatives from the vanuatu marine sponge Crella sp

Continued investigation of cytotoxic extracts of the marine sponge Crella sp. has resulted in the discovery of crellastatins I-M (2-6). Their structures were determined by interpretation of their NMR spectroscopic and FABMS data. These new bis-steroid derivatives exhibited cytotoxic activity against NSCLC cell lines with IC50 values in the range of 1-8 μg/ml.