Gymnastatins F-H, cytostatic metabolites from the sponge-derived fungus Gymnascella dankaliensis

Gymnastatins F - H (2-4) and gymnamide ( 5) have been isolated from the mycelial MeOH extract of the Halichondria sponge-derived fungus Gymnascella dankaliensis. Their stereostructures have been established on the basis of spectroscopic analyses using 1D and 2D NMR techniques. The stereochemistry of gymnastatin H ( 4) was determined by its synthesis. Among these compounds, gymnastatins F ( 2) and G ( 3) possess a unique bicyclo[3.3.1] nonane ring as natural products, and they were found to exhibit potent growth inhibition against the P388 cancer cell line.