FACTOR VIIA INHIBITION BY NATURALLY OCCURRING PEAT HUMIC ACIDS AND SYNTHETIC HUMIC ACID LIKE POLYMERS

摘要

Activated Factor VII (F VIIa), an essential component of the extrinsic activation of blood coagulation, is inhibited by substances of the humic acid (HA) type, which is shown by the prolongation of clotting time in vitro. On the base of IC_(50) values (50% inhibition concentrations) the strongest effect was observed with caffeic acid oxidation product (KOP; 27.6 μg/ml) followed by HS 130 (40.0 μg/ml), HS 136 (43.6 μg/ml), Aldrich HA(51.9 μg/ml), Melanoidin Ml (52.2 μg/ml) and the sodium salt of peat water HA (NaH; 84.2 μg/ml). At lower concentrations HA with the exception of HS 130 and HS 136 reduced the clotting time up to a maximum of 24%. In conclusion, F VIIa besides thrombin and F Xa may be considered a further target of anticoagulatory effective substances of the HA type.