Bacilsubteramide A, a new indole alkaloid, from the deep-sea-derived Bacillus subterraneus 11593.

From the deep-sea-derived bacterium Bacillus subterraneus 11593, a new indole alkaloid (1) was isolated along with three known compounds (2‒4). By detailed analysis of its NMR spectroscopic data, and further by the theoretical ECD calculations, the absolute configuration of the new compound was determined to be (R)-N-[2-(3-hydroxy-2-oxoindolin-3-yl)ethyl]acetamide, and named bacilsubteramide A. All four isolates were tested for anti-allergic bioactivities; however, none exhibited positive effect (IC50  > 0.2 mM). Noteworthily, it is the first report on secondary metabolites from the bacterium B. subterraneus.