Neopetrocyclamines A and B, Polycyclic Diamine Alkaloids from the Sponge <i>Neopetrosia</i> cf <i>exigua</i>

Abstract

Two new polycyclic alkaloids, neopetrocyclamines A and B (<b>1</b> and <b>2</b>), along with the known metabolites papuamine (<b>3</b>) and haliclonadiamine (<b>4</b>), were isolated from the Indonesian sponge <i>Neopetrosia</i> cf <i>exigua</i>. Neopetrocyclamine A contains a formamidinium moiety, a rare functional group. While these compounds share the same basic biosynthetic building blocks, the size of the ring system differs in <b>1</b> and <b>2</b> because of the formamidinium moiety. Biological evaluations of <b>1</b>–<b>4</b> revealed that papuamine is cytotoxic against glioblastoma SF-295 cells (GI₅₀ = 0.8 μM)