Aromatic Polyketides from the Mangrove-Derived Streptomyces sp. SCSIO 40069.

A chemical investigation of sp. SCSIO 40069 resulted in the isolation of a series of aromatic polyketides with rare skeletons, including five new compounds RM18c-RM18g (-) and three known ones (-). Their structures and absolute configurations were determined by diverse methods, including HRMS and NMR spectra, chemical reaction, Snatzke's method, quantum mechanical-nuclear magnetic resonance (QM-NMR), and X-ray crystallographic analysis. Compounds , , , and displayed moderate or weak antibacterial activities.