Galbonolides from Streptomyces sp. SR107

: Genome sequence analysis of Streptomyces sp. LZ35 has revealed a large number of secondary metabolite pathways, including a hybrid fatty acid-type PKS gene cluster-for biosynthesis of galbonolides. By sequence-guided and culture medium selection and with the aid of specific staining on TLC, galbonolides B (1) and E (2)have been identified from strain Streptomyces sp. LZ35. Further discovery and mining of galbonolides from a clean background mutant strain, Streptomyces sp LZ35Aheng (SR107), led to the isolation of galbonolides F (3) and G (4), which were elucidated by analysis of their HRESIMS and NMR spectroscopic data.