New cyclic dipeptide discovered from deep-sea derived Aspergillus sp. HDN20-1401

Area of Science:

• Natural Product Chemistry
• Marine Microbiology
• Medicinal Chemistry

Background:

• Deep-sea derived fungi are a rich source of novel bioactive compounds.
• The Aspergillus genus is known for producing diverse secondary metabolites with pharmaceutical potential.

Purpose of the Study:

• To isolate and characterize new chemical entities from a deep-sea derived Aspergillus sp.
• To evaluate the antimicrobial and anticancer activities of the isolated compounds.

Main Methods:

• Isolation and purification of compounds using chromatographic techniques.
• Structure elucidation employing Nuclear Magnetic Resonance (NMR) spectroscopy, High-Resolution Electrospray Ionization Mass Spectrometry (HRESIMS), and Electronic Circular Dichroism (ECD) calculations.
• Antimicrobial activity assessed by Minimum Inhibitory Concentration (MIC) assays.

Main Results:

• A new alkaloid, aspergilalkaloid A (1), featuring a pyridoindole hydroxymethyl piperazine dione structure, was identified.
• Six known compounds (2-7) were also isolated and characterized.
• Aspergilalkaloid A (1) exhibited notable inhibitory activity against Bacillus cereus (MIC = 12.5 μM) and weak activity against Methicillin-resistant Coagulase-Negative Staphylococcus Aureus (MRCNS).

Conclusions:

• Aspergilalkaloid A is a novel alkaloid with promising antimicrobial properties against Gram-positive bacteria.
• This discovery underscores the potential of deep-sea fungi as a source for new antimicrobial drug leads.