Effects of the extract from Conyza canadensis on human blood platelet aggregation

The effects of different parts of extract from medicinal plant Conyza canadensis, used to control bleeding, on human blood platelet aggregation in vitro were investigated. Aqueous extract of Conyza c. from young or old plants, glycoconjugate part, polysaccharide part and aglycon part at the concentrations above 0.75 mg/ml strongly inhibited platelet aggregation induced by collagen (2 mu g/ml) in dose-dependent manner. Polysaccharide part isolated from plant extract had the strongest inhibitory effect on aggregation stimulated by collagen and seems to be responsible for antiaggregatory properties.