New Steroidal Alkaloids from the Marine Sponge Corticium niger that Inhibit Growth of Human Colon Carcinoma Cells

Colorectal cancer is the third leading cause of cancer-related deaths in both men and women in the United States. About 50% of diagnosed patients are estimated to die from colon cancer, thus highlighting the need for improved chemotherapeutic agents. The testing of extracts from the extensive natural products repository of the National Cancer Institute (NCI) in the NCI 60-cell line screen identified several extracts with selective activity against the colon cancer cell line panel. Bioassay-guided fractionation of a selectively cytotoxic extract from the marine sponge Corticium niger led to the isolation of new steroidal alkaloids along with three known compounds. The structures of these compounds were elucidated by interpretation of 1D and 2D NMR spectroscopic data and accurate mass measurements (HR-EIMS).