The fungus Eurotium sp., derived from the marine sponge Ircinia variabilis, was found to produce a diketopiperazine-indole alkaloid that we named fintiamin (1). Structural elucidation of 1 was achieved by extensive spectroscopic analysis including nuclear magnetic resonance spectroscopy and mass spectrometry. Compound 1 is a lipophilic terpenoid-dipeptide hybrid molecule that shows affinity for the cannabinoid CB1 receptor at low micromolar concentrations. Docking studies based on previous X-ray structures provide a plausible binding pose for compound 1 in the orthosteric binding site of the CB1 receptor.
Keywords: Eurotium sp.; cannabinoid receptors; diketopiperazine; marine endophytes; marine natural products.
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