Ulleungamides A and B, Modified 伪,尾-Dehydropipecolic Acid Containing Cyclic Depsipeptides from Streptomyces sp. KCB13F003
文摘
Two novel cyclic depsipeptides, ulleungamides A (1) and B (2), were isolated from cultures of terrestrial Streptomyces sp. Their structures were determined by analyses of spectroscopic data and various chemical transformations, including modified Mosher鈥檚 method, advanced Marfey鈥檚 method, PGME, GITC derivatizations, and Snatzke鈥檚 method. Ulleungamides were determined to be a new class of peptides bearing unprecedented units, such as 5-hydroxy-6-methyl-2,3-dehydropipecolic acid, 4,5-dihydroxy-6-methyl-2,3-dehydropipecolic acid, and amino-linked 2-isopropylsuccinic acid. Ulleungamide A displayed growth inhibitory activity against Staphylococcus aureus and Salmonella typhimurium without cytotoxicity.