Bioactive alkaloids from the Red Sea marine Verongid sponge Pseudoceratina arabica

Three new dibrominated alkaloids, ceratinines F-H (2-4), together with the known compounds molokia'iamine (1), psammaplysin A (5), ceratinamide A (6), 19-hydroxyceratinamide A (7), psammaplysin E (8) and ceratinophenol A (9) were isolated from a new collection of the Red Sea marine sponge Pseudoceratina arabica. The structures of the isolated compounds were assigned by different spectral data including 1D and 2D NMR and HRMS. The compounds were evaluated for their antimigratory activity against the highly metastatic human breast cancer cell line MDA-MB-231 as well as for their antiproliferative activity against HeLa cells. Compound 8 showed potent antimigratory activity with IC50 value of 0.31 μM, while 9 displayed moderate activity with IC50 of 10.4 μM. In addition, compounds 4 and 8 showed potent antiproliferative activities against HeLa cells with IC50 values of 2.56 and 2.19 μM, respectively.