Identification and Fibrinolytic Evaluation of an Isoindolone Derivative Isolated from a Rare Marine Fungus Stachybotrys longispora FG216

An isoindolone derivative, Fungi fibrinolytic compound (R)-2,5-bis((2R,3R)-2-((E)-4,8-dimethylnona-3,7-dien-1-yl)-3,5-dihydroxy-2-methyl-7-oxo-3,4,7,9-tetrahydropyrano[2,3-e]isoindol-8(2H)-yl)pentanoic acid (FGFC1, Fungi fibrinolytic compound 1), was isolated from a rare marine microorganism strain Stachybotrys longispora FG216. The structure of FGFC1 was elucidated by 1H NMR, 13C NMR, IR, and MS data; moreover, it was also evaluated for fibrinolytic activity in vitro and in vivo. The results showed that 0.1–0.4 mmol/L of FGFC1 could stimulate generation of plasmin activity (increased by 2.05–11.44 folds) by measuring Glu-plasminogen and Lys-plasminogen activation in vitro. The experiment of fluorescein isothiocyanate (FITC)-fibrinogen degradation indicated that the effect of FGFC1 on fibrinolytic activity was mediated by plasminogen and scuPA. In addition, FGFC1 (10 mg/kg) could dissolve most of pulmonary thrombus of Wistar rat in vivo. It is possible that FGFC1 is a potential thrombolytic agent in the future.