Cytotoxic activity of alkyl benzoate and fatty acids from the red sea sponge Hyrtios erectus.

The chemical investigation of the methylene chloride fraction of marine sponge Hyrtios erectus led to the isolation of the known oxysterol (2) along with a new alkyl benzoate compound identified by spectroscopic methods (NMR and MS) as 4'-methylheptyl benzoate (1), whilst the n-butanol fraction afforded the known indole 3-carbaldehyde and β-carboline derivatives. Moreover, the hexane fraction was analysed by GC-MS for their fatty acids (FAs). A total of 17 FAs with chain lengths between 14 and 25 carbons were identified. Methyl-branched FAs are predominated suggesting the presence of bacterial symbionts in the H. erectus sponge. Furthermore, compounds 1 and 2 displayed significant cytotoxicity against breast adenocarcinoma (MCF-7) with IC50 values of 2.4 and 3.8 μM, respectively, since compound 2 was also shown to have potent cytotoxic effect against hepatocellular carcinoma cells (HepG 2) with IC50 value of 1.3 μM.