Geobarrettin D, a Rare Herbipoline-Containing 6-Bromoindole Alkaloid from Geodia barretti .

Geobarrettin D ( 1 ), a new bromoindole alkaloid, was isolated from the marine sponge Geodia barretti collected from Icelandic waters. Its structure was elucidated by 1D, and 2D NMR (including ¹ H- ¹⁵ N HSQC, ¹ H- ¹⁵ N HMBC spectra), as well as HRESIMS data. Geobarrettin D ( 1 ) is a new 6-bromoindole featuring an unusual purinium herbipoline moiety. Geobarrettin D ( 1 ) decreased secretion of the pro-inflammatory cytokine IL-12p40 by human monocyte derived dendritic cells, without affecting secretion of the anti-inflammatory cytokine IL-10. Thus, compound 1 shows anti-inflammatory activity.