Zarzissine, a new cytotoxic guanidine alkaloid from the Mediterranean sponge Anchinoe paupertas.

From a CH2Cl2 extract of the Mediterranean sponge Anchinoe paupertas were isolated and characterized zarzissine [2], a new 4,5-guanidino-pyridazine compound and the known p-hydroxybenzaldehyde [1]. The structure of zarzissine [2] was elucidated by spectroscopic methods, including the application of a number of 2D nmr techniques. Biological activities of compounds 1 and 2 were also determined, with zarzissine exhibiting cytotoxicity against three human and murine tumor cell lines.