Discovery of Anti-MRSA Secondary Metabolites from a Marine-Derived Fungus .

Methicillin-resistant (MRSA), a WHO high-priority pathogen that can cause great harm to living beings, is a primary cause of death from antibiotic-resistant infections. In the present study, six new compounds, including fumindoline A-C (-), 12, 13-hydroxy-asperfumigatin (), 2--tryptoquivaline F () and penibenzophenone E (), and thirty-nine known ones were isolated from the marine-derived fungus H22. The structures and the absolute configurations of the new compounds were unambiguously assigned by spectroscopic data, mass spectrometry (MS), electronic circular dichroism (ECD) spectroscopic analyses, quantum NMR and ECD calculations, and chemical derivatizations. Bioactivity screening indicated that nearly half of the compounds exhibit antibacterial activity, especially compounds and , and - showed excellent antimicrobial activities against MRSA, with minimum inhibitory concentration (MIC) values ranging from 1.25 to 2.5 μM. In addition, compound showed moderate inhibitory activity against (MIC: 25 μM), compound showed moderate inhibitory activity against (MIC: 50 μM), and compound showed strong inhibitory activity against the hatching of a egg (IC: 2.5 μM).