Study on the antithrombotic activity of Umbilicaria esculenta polysaccharide.

Umbilicaria esculenta as a traditional food is known to have many pharmacological activities, such as cholesterol synthesis inhibition, anti-inflammation and anti-tumor. The antithrombotic activities of UEP isolated from the lichen were examined in vitro and in vivo for the first time. The in vitro anticoagulant activity of UEP was tested by its PT, APTT and TT. The more prolongation of APTT suggested a more obvious inhibition of the intrinsic coagulation systems than the extrinsic. Its antithrombotic properties were evaluated using an arteriovenous shunt thrombosis model in rats, and its inhibition of thrombus formation increased in a dose-dependent manner. It also caused a dose-dependent increase in tail transection bleeding time. Oral administration of UEP also showed a significant dose dependent preventive effect against thrombotic death or paralysis. UEP has a potent antithrombotic effect in vitro and in vivo, which may be used as a novel, effective and promising antithrombotic agent.