Scopularides A and B, Cyclodepsipeptides from a Marine Sponge-Derived Fungus, Scopulariopsis brevicaulis

Two novel cyclodepsipeptides, scopularides A and B, were found in the fungus Scopulariopsis brevicaulis, which was isolated from the marine sponge Tethya aurantium. In addition, the known fungal metabolite paxilline was identified. The structures of the scopularides were elucidated by NMR, MS, and chemical derivatization methods as cyclo-(3-hydroxy-4-methyldecanoyl-Gly-L-Val-D-Leu-L-Ala-L-Phe) and cyclo-(3-hydroxy-4-methyloctanoyl-Gly-L-Val-D-Leu-L-Ala-L-Phe) for scopularide A and B, respectively. Antibiotic activity against Gram-negative bacteria was absent and against Gram-positive bacteria was weak, but activity against several tumor cell lines was significant at 10 microg/mL.