Sacchaindols A-C, Dimeric Alkaloids with Anti-inflammatory Activity from Marine Sediment-Derived Mutant Strain Saccharopolyspora erythraea SCSIO 07745/Δspo11.

Two novel types of dimeric alkaloids were isolated from the marine sediment-derived mutant strain Saccharopolyspora erythraea SCSIO 07745/Δspo11. Among them, sacchaindol A (1) represents a previously unreported class of dimeric aminoquinolinone alkaloids, whereas sacchaindols B (2) and C [(±)-3] comprise a rare fused 6/6/5/5 tetracyclic indole alkaloid framework. Their structures were elucidated using a combination of spectroscopic analyses, single-crystal X-ray diffraction, and computational methods. Hypothetical biosynthetic pathways for 1-3 were proposed. Notably, sacchaindols C [(±)-3] exhibited anti-inflammatory activity.