Indole derivatives including bromoindoles have been isolated from the South Pacific marine sponges Rhopaloeides odorabile and Hyrtios sp. Their structures were established through analysis of mass spectra and 1D and 2D NMR spectroscopic data. Their potential inhibitory phospholipase A2 (PLA2), antioxidant and cytotoxic activities were evaluated. The new derivative 5,6-dibromo-l-hypaphorine (9) isolated from Hyrtios sp. revealeda weak bee venom PLA2 inhibition (IC50 0.2 mM) and a significant antioxidant activity with an Oxygen Radical Absorbance Capacity (ORAC) value of 0.22. The sesquiterpene aureol (4), also isolated from Hyrtios sp., showed the most potent antioxidant activity with an ORAC value of 0.29.
Nine new cyclodepsipeptides, homophymines B–E (2–5) and A1–E1 (1a–5a), were isolated from the polar extracts of the sponge Homophymia sp. The new structures, featuring new polyketide-derived end groups, were determined by interpretation of NMR and MS data. The configurations of the new end groups was secured by the application of J-based configurational analysis. Homophymines displayed very potent antiproliferative activity (IC50 in the nM range) against a panel of human cancer cell lines.