Grenadadiene and grenadamide, cyclopropyl-containing fatty acid metabolites from the marine cyanobacterium Lyngbya majuscula.

Grenadadiene (1), debromogrenadiene (2), and grenadamide (3), three structurally unique cyclopropyl-containing metabolites, were isolated from the organic extract of a Grenada collection of the marine cyanobacterium Lyngbya majuscula. The structures and the relative stereochemistries of these compounds were determined using spectroscopic methods. These are the first reported cyclopropyl-containing fatty acid derivatives from a Lyngbya sp. Grenadadiene (1) has an interesting profile of cytotoxicity in the NCI 60 cell line assay, while grenadamide (2) exhibited modest brine shrimp toxicity (LD50 = 5 microg/mL) and cannabinoid receptor binding activity (Ki = 4.7 microM).