Eunicellin-based diterpenoids from the cultured soft coral Klyxum simplex

Eight new eunicellin-base diterpenoids, klysimplexins A–H (1–8), were isolated from a cultured soft coral Klyxum simplex. Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The structure of 1 was further confirmed by a single-crystal X-ray diffraction analysis and the application of modified Mosherʹs method. Metabolites 2 and 8 were found to be cytotoxic toward a limited panel of cancer cell lines.