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.