Anticoagulant and anti-platelet activity of polyphenolic-polysaccharide preparation isolated from the medicinal plant Erigeron canadensis L.

The polyphenolic-polysaccharide preparation from Erigeron canadensis L. was isolated by multi-step process, characterized by chromatographic and spectroscopic methods, and was subjected to anion-exchange chromatography. The whole preparation demonstrated in vivo anticoagulant activity, and the effect was neutralized by protamine sulfate. It had also anti-platelet activity, limited to the cyclooxygenase pathway, induced by arachidonic acid. The plant preparation was fractionated to receive the fraction of the highest anticoagulant activity - 7-9IU/mg of heparin standard, expressed in aPTT. The influences of the plant preparation as well as its the most active fraction on thrombin and factor Xa inactivation by antithrombin, and on thrombin inhibition by heparin cofactor II, were compared. The both tested plant preparations inhibited thrombin as well as factor Xa amidolytic activities in the presence of antithrombin, but much higher concentrations were required to obtain the same effects like for unfractionated heparin. The mechanisms of anticoagulant activity in the case of the plant preparation are based on interactions with heparin cofactor II, to inactivate thrombin. Chromatographic and spectroscopic methods revealed its macromolecular polyanionic non-sulfated polyphenolic-polysaccharide conjugate, with carboxylic groups. The polysaccharide part constituted 32% of the total mass and was homogenous, with molecular mass 38kDa, containing mainly hexuronic acids, and much smaller amounts of glucose, arabinose, galactose, as well as some traces of mannose, xylose and rhamnose. Polyphenolic part, with molecular mass >12.5kDa, was rich in hydroxylic rests as well as in carboxylic groups, free and esterified. The polyphenolic-polysaccharide preparation from E. canadensis may become a new source of anticoagulant compound potentially useful in anticoagulant and anti-platelet therapy.