Inhibition of blood platelet adhesion, aggregation and secretion by Artemisia dracunculus leaves extracts

Background: Platelet hyperactivity plays an important role in atherosclerosis and arterial thrombosis. Artemisia dracunculus L. (tarragon) is a common table vegetable all over Iran and known for its anticoagulant activity in Iranian folk medicine. Objective: The present study was undertaken to investigate the effect of Artemisia dracunculus leaves methanol crude extract and its chloroform fraction on platelet aggregation, secretion and adhesion to laminin coated plates. Materials and methods: Human platelets were incubated with different concentrations of the test sample (equivalent to 25-200 mu g of plant leaves powder/ml). The treated and untreated platelets were then activated with thrombin and adhesion to the laminin coated plates were evaluated. Results: Based on our observations, the methanol extract and its chloroform fraction, at a concentration of 200 mu g/ml, inhibited platelet adhesion to laminin coated wells by 50% and 60%, respectively. In addition to alternation of cell adhesive properties, protein secretion and self aggregation of the treated platelets were decreased upon treatment with the crude extract and its chloroform fraction. Conclusions: Our results showed that the methanol crude extract and chloroform fraction of tarragon could inhibit platelets adhesion, aggregation and secretion. These findings provide scientific basis for the traditional use of tarragon as a blood-diluting factor, as locally called, or as an anticoagulant. (c) 2007 Elsevier Ireland Ltd. All rights reserved.