Induced production, synthesis, and immunomodulatory action of clostrisulfone, a diarylsulfone from clostridium acetobutylicum

The anaerobe Clostridium acetobutylicum belongs to the most important industrially used bacteria. Whereas genome mining points to a high potential for secondary metabolism in C. acetobutylicum , the functions of most biosynthetic gene clusters are cryptic. We report that the addition of supra‐physiological concentrations of cysteine triggered the formation of a novel natural product, clostrisulfone ( 1 ). Its structure was fully elucidated by NMR, MS and the chemical synthesis of a reference compound. Clostrisulfone is the first reported natural product with a diphenylsulfone scaffold. A biomimetic synthesis suggests that pentamethylchromanol‐derived radicals capture sulfur dioxide to form 1 . In a cell‐based assay using murine macrophages a biphasic and dose‐dependent regulation of the LPS‐induced release of nitric oxide was observed in the presence of 1 .