Indimicins A–E, Bisindole Alkaloids from the Deep-Sea-Derived <i>Streptomyces</i> sp. SCSIO 03032

Five new bisindole alkaloids, indimicins A–E (<b>1</b>–<b>5</b>), bearing a unique 1′,3′-dimethyl-2′-hydroindole moiety, were isolated from the marine-derived <i>Streptomyces</i> sp. SCSIO 03032, along with two new compounds, lynamicins F and G (<b>6</b> and <b>7</b>). Their planar structures were elucidated by detailed interpretation of their MS and NMR spectroscopic data, and the absolute configurations were determined by X-ray crystallographic analysis (for <b>1</b>), comparison of CD spectra (for <b>2</b>–<b>4</b>), and quantum chemical calculations (for <b>5</b>). Indimicin B (<b>2</b>) exhibited moderate cytotoxic activity toward the MCF-7 cell line