3-Hydroxy-3-(2-oxopropyl)indolin-2-one, a product of a human-derived Enterocloster strain, is an inhibitor of nitric oxide production

When cultured anaerobically, Enterocloster sp. RD014215 was found to produce 1 . Using nuclear magnetic resonance and mass spec- troscopy, the planar structure of 1 was determined to be 3-hydroxy-3-(2-oxopropyl)indolin-2-one. The chirality of 1 was implied as S by comparing the optical rotation value of 1 with literature reports of the synthesized compounds. To our knowledge, this work represents the first discovery of the metabolite produced by Enterocloster strain. 1 exhibited inhibition of nitric oxide (NO) production, demonstrating a 50% inhibitory activity (IC50 ) of 34 μm for NO production by murine macrophage cells subjected to lipopolysaccharide stimulation.