Njaoamines A–F, new cytotoxic polycyclic alkaloids from the haplosclerid sponge Reniera sp.

Six new cytotoxic polycyclic alkaloids containing an 8-hydroxyquinoline moiety, njaoamines A–F (1–6), have been isolated from the 2-propanol extract of the sponge Reniera sp. collected in Tanzania. Their structures were determined by extensive analysis of their spectroscopic features, particularly 1D and 2D NMR spectra recorded in Py-d5. Cytotoxicity of the compounds isolated was evaluated against a panel of three human tumor cell lines.