Further minor metabolites of staurosporine produced by a Streptomyces longisporoflavus strain.

From the staurosporine producing strain R-19 Streptomyces longisporoflavus various minor metabolites were isolated: They include new compounds with a keto function at carbon 4' of staurosporine and several metabolites related to TAN-1030A. The new structures were elucidated by spectroscopic methods, mainly 1H NMR and 13C NMR and by comparison with TAN-1030A. The new compounds inhibited protein kinase C with IC50 values in the micromolar range with the exception of those compounds that are alkylated at the lactam nitrogen.