Cytotoxic Anomoian B and Aplyzanzine B, New Bromotyrosine Alkaloids from Indonesian Sponges

Two new bromotyrosine derivatives, anomoian B (1) and aplyzanzine B (2), were isolated, respectively, from the organic extracts of a Verongida sponge belonging to the Hexadella genus and from a two-sponge association (Jaspis sp. and Bubaris sp.), both collected off the coast of Indonesia. The planar structure of 1 and 2 was determined by 1D and 2D NMR experiments and by high-resolution mass spectrometry, while their absolute stereochemistry was assigned by comparison with optical rotation values of known bromotyrosines and by chemical degradation. Both compounds showed moderate antiproliferative activity against a panel of different cancer cell lines. Their cytotoxic activity is facilitated through the induction of apoptosis, which is mediated neither by the generation of reactive oxygen species nor by the inhibition of histone deacetylases in these cell lines.