Angucyclinones from an Indonesian Streptomyces sp.

Six new angucyclinone polyketides named panglimycins A-F were isolated together with the three known metabolites (+)-fujianmycin A, (+)-ochromycinone, and emycin C from the bioassay-guided fractionation of the extract of the Indonesian Streptomyces strain ICBB8230. The new compounds are highly oxygenated angucyclinones that appear to be biosynthetically derived from ochromycinone or fujianmycin. Their structures were determined by X-ray crystal analysis, interpretation of 1D- and 2D-NMR spectra, and comparison of the data with those of structurally related known natural products. Despite structural similarities to angucyclinones with antibiotic activities, the panglimycins did not exhibit any growth inhibition when tested against several bacteria and fungi.