SF2809 compounds, novel chymase inhibitors from Dactylosporangium sp. 1. Taxonomy, fermentation, isolation and biological properties

Six novel chymase inhibitors, SF2809-I, SF2809-II, SF2809-III, SF2809-IV, SF2809-V and SF2809-VI, were isolated from the fermentation broth of an actinomycete strain SF2809. The strain was identified as Dactylosporangium sp. by morphological, chemotaxonomical and phylogenetic studies. These six novel compounds inhibited recombinant human chymase in the range between IC50 of 0.014 and 7.3 microM. However, they showed little or no inhibitory activity against chymotrypsin or cathepsin G, even though these two and chymase belong to the chymotryptic serine protease family. This result indicates that these compounds work as specific chymase inhibitors.