Cyclomarins A−C, New Antiinflammatory Cyclic Peptides Produced by a Marine Bacterium (Streptomyces sp.)

Three new cyclic heptapeptides, cyclomarins A−C (1−3), were isolated from extracts of a cultured marine bacterium collected in the vicinity of San Diego, CA. The major metabolite, cyclomarin A (1), contains three common and four unusual (or unique) amino acids. The structures of the new metabolites were determined using 1D and 2D NMR methods, and the stereochemistry was determined from an X-ray crystal structure of the diacetate derivative of 1. Cyclomarin A (1) displays significant antiinflammatory activity in both in vivo and in vitro assays.