Novel Macrolactams from a Deep-Sea-Derived Streptomyces Species

Four polyene macrolactams including the previously reported niizalactam C ( ), and three new ones, streptolactams A-C ( - ) with a 26-membered monocyclic, [4,6,20]-fused tricyclic and 11,23-oxygen bridged [14,16]-bicyclic skeletons, respectively, were isolated from the fermentation broth of the deep-sea sediment-derived sp. OUCMDZ-3159. Their structures were determined based on spectroscopic analysis, X-ray diffraction analysis, and chemical methods. The abiotic formation of compounds and from compound were confirmed by a series of chemical reactions under heat and light conditions. Compounds and showed a selective antifungal activity against ATCC 10231.