Bromopyrrole-Imidazole Alkaloids (oroidin), and its Conversion Molecule (Dihydrooroidin) Isolated from a Marine Sponge (Agelas nemoecinata)

Oroidin (1) is a bromopyrrole-imidazole alkaloid widely distributed in marine sponges of the order Agelasida. The compound exhibits potent cytotoxicity against several tumor cells. Oroidin serves as a prototype building block, giving rise to many bromopyrrole alkaloids. This study aims to re-analysis of the isolated bromopyrrole-related alkaloids derived from oroidin and propose the conversion mechanism. Marine sponge was collected by SCUBA diving at the depth of 15 meters. It was macerated in methanol before extracted by ethyl acetate to yield 2 grams. Crud extract was subsequently isolated by column chromatography method using to RP18 and Si-gel as adsorption material.Structure determination of the isolated compounds were re-analyzed by spectroscopic methods.By comparison the spectroscopic data both mass and 1 H-NMR with the literature, compound 1 and 2 was confirmed to be oroidin and dihydrooroidin, respectively.