Effects of Medium Molecular Weight Heparinyl Phenylalnine on Superoxide Dismutase Activity in Mice.

We investigated the radical scavenging ability of heparin (HE), medium molecular weight heparinyl phenylalanine (MHF) and medium molecular weight heparinyl leucine (MHL) in the blood of mice. The extracellular superoxide dismutase (EC-SOD) activity was measured according to the method by Oyanagui and Sato. As a result, HE significantly increased the EC-SOD activity with a significant prolongation of activated partial thromboplastin time (APTT), while MHF and MHL significantly increased the EC-SOD activity without a prolongation of APTT. Dose-response curve at 20 min after the injection of each compound indicated a bell-shape. Changes in the plasma EC-SOD activity of mice after the administration of HE, MHF and MHL (10 mg/kg/10 ml) were investigated time-dependently. The plasma EC-SOD activity peaked at 5 min after the administration of all compounds. These results indicated that MHF and MHL show a radical scavenging ability by increasing the EC-SOD activity and MHF may be a candidate for clinical use.