The effects of
nattokinase on the in vitro platelet aggregation and in vivo
thrombosis were investigated in comparison with
aspirin. Rabbit platelet-rich plasma was incubated with
nattokinase and aggregation inducers
collagen and
thrombin, and the platelet aggregation rate was analyzed.
Nattokinase significantly inhibited both the
collagen- and
thrombin-induced platelet aggregations.
Nattokinase also reduced
thromboxane B2 formation from
collagen-activated platelets in a concentration-dependent manner. Rats were orally administered with
nattokinase for 1 week, and their carotid arteries were exposed. Arterial
thrombosis was induced by applying 35% FeCl3-soaked filter paper for 10 min, and the blood flow was monitored with a
laser Doppler probe.
Nattokinase delayed the FeCl3-induced
arterial occlusion in a dose-dependent manner, doubling the occlusion time at 160 mg/kg. In addition, a high dose (500 mg/kg) of
nattokinase fully prevented the occlusion, as achieved with
aspirin (30 mg/kg). The results indicate that
nattokinase extracted from fermented soybean inhibit platelet aggregation by blocking
thromboxane formation, and thereby delay
thrombosis following oxidative arterial wall injury. Therefore, it is suggested that
nattokinase could be a good candidate without adverse effects for the improvement of blood flow.