Staurosporine, a Potent Platelet Aggregation Inhibitor from aStreptomycesSpecies

Abstract
We found a potent platelet aggregation inhibitor in the culture broth of Streptomyces strain M-193. The inhibitor was purified as white crystals and investigated; it was identified as staurosporine. It strongly inhibited the platelet aggregation induced by collagen or ADP with IC50 values of 3.4 μm, and 11.6 μm, respectively. The inhibitor had no effect on thrombin-induced platelet aggregation or membrane stabilization against heat-induced hemolysis.