Screening of endophytic fungi with antithrombotic activity and identification of a bioactive metabolite from the endophytic fungal strain CPCC 480097.

Fermentation extracts from 1,075 endophytic fungi were screened by the Markwardt method. The endophytic strain CPCC 480097 had the strongest antithrombotic activity and was identified as Fusarium sp. based on morphologic tests and internal transcriptional spacer sequence analysis. The target of the antithrombotic agent from the endophytic strain CPCC 480097 was identified by analysis of the fibrinogen clotting time, amidolytic activity, and fibrinolytic assay. The results showed that this antithrombotic agent is a 28-kDa single-chain fibrinolytic enzyme. The identification of this fibrinolytic enzyme was performed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The two internal sequences of this enzyme were obtained, and these showed no homology with those of other known fibrinolytic enzymes.