SALINAMIDES, ANTIINFLAMMATORY DEPSIPEPTIDES FROM A MARINE STREPTOMYCETE

In addition to the previously reported antiinflammatory agents salinamides A and B from the marine isolate Streptomyces sp. CNB-091, three minor peptides are described. Their total structures were established using a combination of spectral and chemical techniques. Revised structures are presented for the bicyclic depsipeptides salinamides A and B on the basis of the analysis of the dansylated salinamide A hydrolysate by chiral capillary electrophoresis. The fermentation yield of salinamide D, which contains a d-valine residue in place of the d-isoleucine moiety in salinamide A, can be dramatically increased 30-fold by supplementing the growth media with l-valine. Salinamides C and E are monocyclic depsipeptides that are likely methylated byproducts of salinamide A biosynthetic intermediates.