Two new aromatic polyketides from a sponge-derived Fusarium

Area of Science:

• Marine Natural Products Chemistry
• Mycology
• Chemical Biology

Background:

• Marine fungi are a prolific source of novel bioactive compounds.
• The screening of marine-derived microorganisms is crucial for discovering new therapeutic agents.
• Sponge-associated fungi represent an underexplored niche for natural product discovery.

Purpose of the Study:

• To isolate and characterize new aromatic polyketides from a sponge-associated fungus.
• To evaluate the bioactivity of the isolated compounds, particularly against multidrug-resistant bacteria.

Main Methods:

• Isolation and purification of compounds using chromatographic techniques.
• Structure elucidation of new compounds employing Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS).
• Computational analysis, including Density Functional Theory (DFT) based chemical shift calculations, aided NMR assignment.

Main Results:

• Two new aromatic polyketides, karimunones A (1) and B (2), were identified.
• Five known compounds (3-7) were also isolated from the Fusarium sp. KJMT.FP.4.3.
• Karimunone B (2) exhibited antibacterial activity against multidrug-resistant Salmonella enterica serovar Typhi with a Minimum Inhibitory Concentration (MIC) of 125 µg/mL.

Conclusions:

• The study successfully identified novel aromatic polyketides from a marine-derived fungus.
• Karimunone B shows potential as an antibacterial agent against a significant human pathogen.
• Further investigation into karimunone B's mechanism of action and structure-activity relationship is warranted.