Subtipyrrolines A–C, novel bioactive alkaloids from the Mariana Trench-associated bacterium Bacillus subtilis SY2101

Abstract

Abstract The new subtipyrrolines A–C were discovered from the hadal bacterium Bacillus subtilis SY2101 isolated from a sample of sediment collected at the Mariana Trench. Their structures were elucidated based on the HRESIMS data, extensive NMR spectroscopic analyses, ECD and 13C NMR calculations, and single crystal X-ray diffraction experiment. Subtipyrrolines A–C possessed an unprecedented pyrrole-pyrrole-dihydropyridine tricyclic skeleton. Subtipyrrolines A and C showed weak antiproliferative activities against human glioma U251 and U87MG cells, respectively, and subtipyrrolines A–C had weak antimicrobial activities in inhibiting the growth of Escherichia coli and Candida albicans. The plausible biosynthetic pathway of subtipyrrolines A–C was also proposed.