Chemical investigation of an Australian marine sponge, Pseudoceratina sp., collected from Mooloolaba South-East Queensland
has provided a series of bromotyrosine metabolites from a simple modified tyrosine to more elaborate linear compounds. Six
known compounds, (+)-aeroplysinin-1 (1), a mixture of 19-deoxyfistularin-3 (2) and 11-deoxyfistularin-3 (3), 11,19-
dideoxyfistularin-3 (4), aerothionin (5) and homoaerothionin (6) have been isolated together with a new fistularin-3 derivative,
11-deoxy-19-ketofistularin-3 (7). The structures of all compounds were characterised using 1D and 2D NMR techniques, MS
and by comparison with literature data. Two selected fistularin-3 derivative metabolites 4 and 7 were screened for in vitro
activity against chloroquine-sensitive (3D7) P. falciparum malaria parasites and showed antimalarial activity with IC50 values
of 5.4 and 2.8 μM, respectively.