Fibrinolytic effects of Ginkgo biloba extract

A multitude of factors are involved in regulating the blood coagulation homeostatic processes in the body, which may ultimately lead to thromboemboli and thrombosis. The resolution of blood clots after healing is as important as clot formation at the site of a vascular lesion. This is accomplished by fibrinolytic drugs such as streptokinase (SK) and urokinase.It must be noted that administration of SK may be accompanied by the lysis of blood clots in unwanted sites, and complications such as general lytic conditions, severe hemorrhaging, reduced serum fibrinogen and allergies can occur. Anti-SK antibodies neutralize the effects of SK. Studies on natural compounds and medicinal herbs with fewer side effects have been ongoing. In the present study, the fibrinolytic effect of Ginkgo biloba, an herb grown in Iran, was investigated.A polyphenolic method was used to obtain Ginkgo extract from its leaves. The fibrinolytic effects of SK (positive control) were compared with those of Ginkgo extract using a fluorometry method.In producing a labelled clot, fibrinogen was labelled with the fluorescent agent fluorescein isothiocyanate and precipitated in the presence of Ca(2+). SK (100 U/mL to 1000 U/mL) and Ginkgo extract were added to labelled fibrin in a plasma environment at dilutions of 1, 1:10, 1:100 and 1:1000 (volume/volume). The fluorescence of the solution was measured between 15 min and 60 min later.A linear relationship was observed between the fluorescence measured and SK concentrations ranging from 300 U/mL to 700 U/mL. Ginkgo extract displayed a remarkable effect in resolving the clot. As Ginkgo extract remained in the environment, fluorescence increased notably, showing a time-dependent relationship.Overall, the results indicate that the effects of Ginkgo extract on the fibrinolytic system are similar to those of SK; hence, this herbal extract can be used as a complement to or a substitute for SK. Additionally, it is proposed that the effects of the active ingredients of Ginkgo extract should be studied in animals. Further studies are warranted for evaluating the possible side effects and toxicity of Ginkgo extract in human subjects.