Metabolomic profile, structural identification and biological activity of bioactive compounds from marine <i>penicillium</i> sp. isolated from the Mediterranean Sea

Diverse bioactive compounds were derived from the marine <i>Penicillium sp.</i> EMS8, isolated from the Mediterranean Sea, Abu Qir coast, Alexandria, Egypt. The large-scale cultivation of EMS8 on solid media led to an ethyl acetate extract with high anti-microbial activity against various pathogenic strains. The metabolomic profile of the strain extract obtained by LC-HRMS/MS analysis and dereplication, revealed the presence of 396 compounds. Subsequent data processing using MassHunter and MZmine 2.5 enabled the construction of a feature-based molecular network on the Global Natural Products Social Molecular Networking (GNPS) platform, followed by visualisation in Cytoscape. The revealed clusters of structurally related molecules, including several chlorinated compounds indicated by characteristic isotopic patterns and similar DAD spectra. The extract was then submitted to a series of chromatographic purifications resulting in a new amide derivative; methyl (<i>E</i>)-6-((5-methoxy-5-oxopentyl) amino)-6-oxohex-3-enoate (<b>1</b>), and <i>N</i>-acetyl tyrosine methyl ester (<b>2</b>), a new natural product, alongside four chlorinated azaphilone derivatives (<b>3-6</b>), and further eleven known compounds. The structures of isolated compounds were investigated using 1D (¹H,¹³C), 2D (H,H COSY, HSQC, HMBC) NMR, and HR-ESIMS mass spectrometry. The results emphasise the importance of the marine fungus as a rich source of diverse bioactive compounds with high capacity as antimicrobial agent.