Coumamarin: a first coumarinyl calcium complex isolated from nature.

Area of Science:

• Natural Product Chemistry
• Marine Microbiology
• Mycology
• Biochemistry

Background:

• Marine microorganisms are a rich source of novel bioactive compounds.
• Calcium complexes from natural sources are rare, making their discovery significant.
• Aspergillus species are known producers of diverse secondary metabolites.

Purpose of the Study:

• To isolate and characterize novel compounds from marine-derived fungi.
• To identify the first natural calcium complex from a fungal source.
• To evaluate the biological activities, including antimicrobial and cytotoxic effects, of the isolated compounds.

Main Methods:

• Isolation of fungal strain Aspergillus sydowii ASTI from a marine water sample.
• Structure elucidation of compounds using spectroscopic techniques (1D, 2D NMR, HR-ESIMS) and X-ray crystallography.
• Phylogenetic analysis of the 18S rRNA gene sequence for fungal identification.
• Antimicrobial and cytotoxic assays.

Main Results:

• Isolation of Coumamarin, a novel 7-hydroxy-3-methoxy-2-oxo-2H-chromene-6-carboxylate Ca(II) complex, the first natural calcium complex reported.
• Co-isolation of known compounds: diorcinol, violaceol I, hydroxysydonic acid, cyclo (Trp-Phe), kojic acid, ergosterol, and uracil.
• Coumamarin demonstrated potential activity against selected bacteria and yeasts.
• Coumamarin exhibited no cytotoxic activity against the human cervix carcinoma cell line (KB-3-1).

Conclusions:

• Coumamarin represents a significant discovery as the first naturally occurring calcium complex.
• The marine fungus Aspergillus sydowii ASTI is a valuable source of bioactive natural products.
• Coumamarin warrants further investigation for its antimicrobial potential.