Bioactive Polycyclic Tetramate Macrolactams from Lysobacter enzymogenes and Their Absolute Configurations by...

Area of Science:

• Natural Product Chemistry
• Microbiology
• Medicinal Chemistry

Background:

• Lysobacter enzymogenes produces bioactive secondary metabolites.
• Polycyclic tetramate macrolactams are a class of compounds with diverse biological activities.
• The absolute configurations of HSAF and its analogues were previously unestablished.

Purpose of the Study:

• To isolate and characterize new polycyclic tetramate macrolactams from Lysobacter enzymogenes.
• To determine the absolute configurations of isolated compounds.
• To evaluate the cytotoxic and antifungal activities of these natural products.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation via Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR) spectroscopy.
• Assignment of absolute configurations using Electronic Circular Dichroism (ECD) spectral calculations.

Main Results:

• Two new compounds, lysobacteramides A (1) and B (2), were identified alongside known compounds HSAF (3), 3-dehydroxy HSAF (4), and alteramide A (5).
• The absolute configurations of all five compounds were successfully determined.
• Compounds 1-4 exhibited potent cytotoxic effects against human carcinoma cell lines (A549, HepG2, MCF-7).
• Compounds 2 and 3 displayed significant antifungal activity against Fusarium verticillioides.

Conclusions:

• The isolation and absolute configuration determination of lysobacteramides A and B provide new insights into the biosynthesis of polycyclic macrolactams.
• The identified compounds possess promising cytotoxic and antifungal properties, warranting further investigation for therapeutic potential.