Structure of Potential Dithiolopyrrolone Antibiotics Detected from the DART-ToF-MS Spectra of Saccharothrix algeriensis Extract

Dithiolopyrrolone antibiotics, produced by the Saharan mycelial bacterium Saccharothrix algeriensis, are known for their potent biological activities. Biochemical profiling of S. algeriensis culture extract was done by direct analysis in real time and time-of-flight mass spectrometry (DART-ToF-MS). No other study on dithiolopyrrolones by this technique has been published. Eleven dithiolopyrrolone derivatives: thiolutin, butyryl-pyrrothine/iso-butyryl-pyrrothine, senecioyl-pyrrothine/tigloyl-pyrrothine, valeryl-pyrrothine/iso-valeryl-pyrrothine, 2-methyl-3-pentenyl-pyrrothine/2-hexonyl-pyrrothine, iso-hexanoyl-pyrrothine and benzoyl-pyrrothine were characterised by their exact mass measurement and the corresponding molecular formula of each compound. The obtained results confirmed that DART-ToF-MS is an appropriate confirmatory technique for powerful and rapid screening, as well as characterisation of bacterial secondary metabolites.