Cytotoxic alkaloids from the marine sponge Thorectandra sp.

Three beta-carboline alkaloids, Compound 1, 1-deoxysecofascaplysin A (2), and fascaplysin (3), were isolated from the aqueous and organic extracts of the marine sponge Thorectandra sp. The structures of 1 and 2 were determined on the basis of spectral data. Compound 1 inhibited the growth of MCF-7 (breast) with an IC50 of 5.9 microg/mL while Compound 2 inhibited the growth of MCF-7 as well as OVCAR-3 (ovarian) human tumor cell lines with IC50s of 1.5 and 2.2 microg/mL, respectively.