Halogenated cyclic peptides isolated from the sponge Corticium sp

Area of Science:

• Marine Natural Products Chemistry
• Marine Biology
• Organic Chemistry

Background:

• Marine sponges are a rich source of diverse bioactive compounds.
• The genus Corticium is known for its potential pharmacological properties.
• Previous research on Corticium sp. has identified various chemical constituents.

Purpose of the Study:

• To isolate and characterize new bioactive compounds from Fijian specimens of the sponge Corticium sp.
• To investigate the chemical diversity of marine natural products.
• To identify novel peptides with potential biological activities.

Main Methods:

• Fractionation of sponge extracts.
• High-field Nuclear Magnetic Resonance (NMR) spectroscopy for structural elucidation.
• High-Resolution Fast-Atom Bombardment Tandom Mass Spectrometry (HRFT MS/MS) for structural analysis.
• Acid hydrolysis and Marfey's analysis for absolute stereochemistry determination.

Main Results:

• Isolation of the known alkaloid steroid plakinamine A.
• Identification of two new halogenated cyclic peptides: corticiamide A (1) and cyclocinamide B (2).
• Complete structural elucidation of corticiamide A and cyclocinamide B using advanced spectroscopic techniques.
• Determination of the absolute stereochemistry of cyclocinamide B.

Conclusions:

• Corticiamide A and cyclocinamide B are novel halogenated cyclic peptides, representing the first reported peptides from the genus Corticium.
• The discovery expands the known chemical diversity of marine natural products.
• These findings highlight the potential of marine sponges as a source for novel drug discovery.