Four new aaptamine alkaloids from marine sponge Aaptos aaptos

Four new aaptamine alkaloids, named as 9-methoxy-N-demethylaaptanone (1), 3,5-dicarbomethoxy-1, 6- naphthyridine (2), aaptosvanphongs A and B (3 and 4), and three known aaptamine alkaloids as 2-methoxy-3-oxoaaptamine (5), 8,9,9-trimethoxy-9H-benzo[de][1,6]-naphthyridine (6), and demethyl(oxy)aaptamine (7) were isolated from the sponge Aaptos by various chromatographic methods. Their structures were established by extensive spectroscopic analyses (HR-ESI-MS, 1 D and 2 D NMR) and by comparison of the spectral data with those reported in the literature. Compounds 1-7 significantly showed cytotoxic effects against SK-LU-1, MCF-7, HepG2, and SK-Mel-2 cell lines with IC50 values in range from 7.7 +/- 0.8 to 51.4 +/- 1.8 mu M. Among them, compound 7 exhibited the most cytotoxic activity with corresponding IC50 values of 9.2 +/- 1.0, 7.8 +/- 0.6, 8.4 +/- 0.8, and 7.7 +/- 0.8 mu M.

Automated summary

Four new aaptamine alkaloids were isolated from the sponge Aaptos, showing significant cytotoxic effects against various cancer cell lines. One of the compounds exhibited the most potent cytotoxic activity among them.