The isolation and characterization of the known pyrrole alkaloid agelongine (6) and of the new natural product daminin (7), the bromine-free analogue of 6, from a specimen of the marine sponge Axinella damicornis is described. Compound 7 showed significant neuroprotective properties. Moreover, for the supply of sufficient material for future medicinal investigations, a short total synthesis of 7 was developed.