New Polyketides from a Hydrothermal Vent Sediment Fungus Trichoderma sp. JWM29-10-1 and Their Antimicrobial Effects

Marine fungi-derived secondary metabolites are still an important source for the discovery of potential antimicrobial agents. Here, five new polyketides (1, 2, and 6–8) and seven known compounds (3–5 and 9–12) were obtained from the culture of the marine-derived fungus Trichoderma sp. JWM29-10-1. Their structures were identified by extensive spectrographic data analyses, including 1D and 2D NMR, UV, IR, and HR-ESI-MS. Further, the absolute configurations of new compounds were determined by circular dichroism (CD) spectrum and alkali-hydrolysis in combination with the in situ dimolybdenum CD method. Subsequently, the antimicrobial effects of these isolated compounds were assessed by examining the minimal inhibition concentration (MIC) with the broth microdilution assay. Compounds 1 and 2 exhibited potent antimicrobial activity against Helicobacter pylori, including multidrug-resistant strains, with MIC range values of 2–8 µg/mL. Moreover, compound 1 showed significant inhibitory effects on the growth of Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and vancomycin-resistant Enterococcus faecium, which greatly threaten human health. This study demonstrates that chromone derivatives 1–2, especially for 1, could be potential lead compounds for the development of new antimicrobial agents and provides insight for future medicinal chemistry research.