Objective: To explore antithrombotic effects and mechanisms of total alkaloids (VnA) and single alkaloids (Al - A6) from Veratrum nigrum.
Methods: The effects of VnA and Al - A6 on thrombosis and coagulation parameters (APTT, PT and TT) were examined in rat in vivo, while their effects on platelet aggregation induced by ADP and thrombin were determined in rabbit in vitro.
Results: VnA and Al ~ A5 decreased thrombus wet weight and platelet aggregation, increased TT, while they had no influence on APTT or PT. A6 had no obvious effect on thrombus wet weight, platelet aggregation or coagulation parameters.
Conclusions: VnA and Al ~ A5 have antithrombotic activities on venous thrombosis. The effective component in VnA is A2 probably. The antithrombotic effects are possibly related to the inhibition of platelet aggregation and the extension of TT. The cevanine type skeleton of steroidal alkaloids is necessary for antithrombotic activities and the ester substitute at C3 can enhance antithrombotic activities.