Chemical Constituents of the Marine Sponge Aaptos aaptos (Schmidt, 1864) and Their Cytotoxic Activity

Seven compounds (1-7) were isolated from the marine sponge Aaptos aaptos living in the Vietnamese sea. Their structures were determined as 2 hours, 5H,7H,9H-9S-hydroxy-imidazo[1,5-a]pyridine-1,3-dione (1), 3-([9-methylhexadecyl]oxy)propane-1,2-diol 2, 2,3-dihydro-2,3-dioxoaaptamine (3), indol-3-aldehyde (4), methyl indole-3-carboxylate (5) 4-hydroxy-5-(indole-3-yI)-5-oxo-pen tan-2-one (6), and thymidine (7) by extensive analysis of HR-ESI-MS, 1D, and 2D NMR spectral data, as well as by comparison of the spectral data with those reported in the literature. In addition, the absolute configuration of 1 was determined from the experimental ECD spectrum and comparison of this with the theoretical ECD calculations using the TDDFT method. Compounds 1 and 2 were isolated from nature for the first time. Compound 3 induced cytotoxic activity against SK-LU)-1, MCF-7, HepG2, and SK-Mel-2 cell lines with IC50 values of 41.27 +/- 2.63, 40.70 +/- 2.65, 34.31 +/- 3.43, and 36.63 +/- 1.40 mu M, respectively.