| The principle objective of this research has been the isolation and structural elucidation of biologically-assayed active substances from extracts of marine sponges, focusing particularly on nitrogen-containing heteroaromatics. The detection and structural elucidation of these novel compounds were established chiefly by 1D and 2D NMR experiments. A mechanism-based approach based on targeted proteins and enzymes as well as tumor cell lines were available for the detection of biological activity.;A review of the current field of nitrogenous heteroaromatics isolated from marine sponges precedes the focus of this work. The extracts of marine sponges Aaptos aaptos, a Xestospongia species, Zyzzya fuliginosa, and Auletta cf. constricta were examined for their initial activity in biological assays as well as for potential tryptamine-derived heteroaromatics. The sponge Aaptos aaptos afforded the known aaptamine-type compounds, and two derivatives, 200 and 201, were made to probe their structure activity relationship. An undescribed species of Xestospongia provided the new dibenzo (f,ij) (2,7) naphthyridine noramphimedine, 206; the first to be described from this genus. Its structural elucidation and initial activity are discussed. New compounds, damirazoles A (207) and B (208), are 1,3-benzoxazoles isolated from Zyzzya fuliginosa, which are similar to known pyrroloiminoquinones reported from this sponge. Their structural determination and methods used to establish the regiochemistry through NMR, as well as biological activity of makaluvamines 191c and 191j isolated, are discussed. The marine sponge Auletta cf. constricta provided the new class of compounds, milnamides A-C 171, 172a, and 214. These are highly methylated tripeptides containing at tert-leucine, a trimethylated tryptophan, and the new amino acid named homo vinylogous valine (homo V-val). Jasplakinolide was also isolated from this organism, as well as all collections of this organism from different locations in Indonesia and their biological activity in vitro and in vivo are discussed. Finally, the implications of isolation of similar tryptamine-derived compounds from different organisms, which suggests a common source, are discussed. |
