Bromopyrrole Alkaloids from the Sponge <em>Agelas kosrae</em>

Abstract

Two new sceptrin derivatives (1,2) and eight structurally-related known bromopyrrole-bearing alkaloids were isolated from the tropical sponge Agelas kosrae. By a combination of spectroscopic methods, the new compounds, designated dioxysceptrin (1) and ageleste C (2), were determined to be structural analogs of each other that differ at the imidazole moiety. Dioxysceptrin was also found to exist as a mixture of α-amido epimers. The sceptrin alkaloids exhibited weak cytotoxicity against cancer cells. Compounds 1 and 2 also moderately exhibited anti-angiogenic and isocitrate lyase-inhibitory activities, respectively.

Keywords

• sceptrin
• pyrrole-imidazole alkaloids
• marine sponge
• anti-angiogenesis
• isocitrate lyase
• bioactive marine natural products