No abstract

Two new decaline metabolites, wakodecalines A and B, were isolated from a fungus, Pyrenochaetopsis sp. RK10-F058, by screening for structurally unique metabolites using LC/MS analysis. Their structures were determined on the basis of NMR and mass spectrometric measurements. The absolute structures were confirmed by a combination of chemical methods including chemical degradation, a modified Mosher's method and Marfey's method, and comparison of the experimental electronic CD (ECD) spectrum with calculated one. Both compounds had a cyclopentanone-fused decaline skeleton and an N-methylated amino acid moiety derived from a serine. They showed moderate antimalarial activity against the Plasmodium falciparum 3D7 strain.The Journal of Antibiotics advance online publication, 13 September 2017; doi:10.1038/ja.2017.103.

Systematic isolation of microbial metabolites has been performed to construct microbial metabolite libraries or fraction libraries. A novel macrolactam, verticilactam (1), was isolated from a library of Streptomyces spiroverticillatus JC-8444. The structure was determined on the basis of NMR and mass spectrometric measurements. 1 had a unique 16-membered macrolactam skeleton including a β-keto-amide moiety.

No abstract

Two novel quinomycin derivatives, RK-1355A (1) and B (2), and one known quinomycin derivative, UK-63,598 (3), were isolated from a microbial metabolites fraction library of Streptomyces sp. RK88-1355 based on Natural Products Plot screening. The structural elucidation of 1 and 2 was established through two-dimensional NMR and mass spectrometric measurements. They belong to a class of quinomycin antibiotics family having 3-hydroxyquinaldic acid and a sulfoxide moiety. They are the first examples for natural products as a quinoline type quinomycin having a sulfoxide on the intramolecular cross-linkage. They showed potent antiproliferative activities against various cancer cell lines and they were also found to exhibit moderate antibacterial activity.