Phallusialides A-E, Pyrrole-Derived Alkaloids Discovered from a Marine-Derived sp. Bacterium Using MS-Based Metabolomics Approaches.

Integrating MS-based metabolomics approaches, LC-MS-PCA and molecular networking enabled the targeted isolation of five new pyrrole-derived alkaloids, phallusialides A-E (-), from a marine-derived sp. bacterium. The structures of - were elucidated by analysis of their HRMS, MS/MS, and NMR spectroscopic data. The absolute configuration of phallusialide A () was determined on the basis of comparisons of experimental and theoretically calculated ECD spectra. Compounds and exhibited antibacterial activity against methicillin resistant (MRSA) and , with MIC values of 32 and 64 μg/mL, respectively, whereas - showed no antibacterial activity even at 256 μg/mL, yielding important SAR insights for this class of compounds.