Monanchoxymycalin C with anticancer properties, new analogue of crambescidin 800 from the marine sponge .

A new pentacyclic guanidine alkaloid, monanchoxymycalin C () was isolated from a new collection of marine sponge along with the known monanchoxymycalin A (). The structure of was elucidated on the basis of spectroscopic data. Monanchoxymycalin C exhibits cytotoxic activity against human cancer HeLa cells at low micromolar concentrations, induces apoptosis-related death of malignant cells and inhibits cancer cell colony formation.