Gymnastatins and dankastatins, growth inhibitory metabolites of a Gymnascella species from a Halichondria sponge

Four new metabolites, gymnastatins Q (3) and R (4) and dankastatins A (5) and B (6), have been isolated from the mycelial MeOH extract of a fungal strain of Gymnascella dankaliensis separated from a Halichondria sponge. Their stereostructures have been established on the basis of spectroscopic analysis using ID and 2D NMR techniques. All of the isolated metabolites (3-6) exhibited growth inhibition against the P388 cancer cell line. Furthermore, gymnastatin Q (3) showed appreciable growth inhibition against BSY-1 (breast) and MKN7 (stomach) human cancer cell lines.