Four new chlorinated meroterpenoids, merochlorins G-J (1-4), and 10, a dihydronaphthalenedione precursor, along with known merochlorins A (5) and C-F (6-9), were obtained from cultivation of the bacterium strain Streptomyces sp. CNH-189, which was isolated from marine sediment. The planar structures of compounds 1-4 and 10 were elucidated by interpretation of MS, UV, and NMR spectroscopic data. The relative configurations of compounds 1-4 were determined via analysis of nuclear Overhauser effect (NOE) spectroscopic data, after which their absolute configurations were established by comparing the experimental electronic circular dichroism (ECD) spectra of compounds 1-4 to those of previously reported possible enantiomer models and DP4 calculations. Compound 3 displayed strong antibacterial activities against Bacillus subtilis, Kocuria rhizophila, and Staphylococcus aureus, with MIC values of 1, 2, and 2 μg/mL, respectively, whereas compound 1 exhibited weak antibacterial effects on these three strains, with a 16-32 μg/mL MIC value range.
Keyphrases
- bacillus subtilis
- staphylococcus aureus
- silver nanoparticles
- molecular docking
- electronic health record
- high resolution
- density functional theory
- big data
- mass spectrometry
- escherichia coli
- anti inflammatory
- essential oil
- multiple sclerosis
- polycyclic aromatic hydrocarbons
- heavy metals
- molecular dynamics simulations
- ms ms
- wound healing
- molecular dynamics
- artificial intelligence
- solid state
- tandem mass spectrometry