The influence of some 3-amino-2-pyrazoline derivatives on cyclooxygenase and lipoxidase activities.

The influence of 3-amino-1-[m-(trifluoromethyl)-phenyl]-2-pyrazoline (BW 755C), 1-(3,3-diphenylpropyl)-3-amino-5-methyl-2-pyrazoline (KD 785) and 1-(3,3-diphenylpropyl)-3-amino-2-pyrazoline (KD 679) on cyclooxygenase and lipoxidase activities has been studied. All three compounds inhibited soybean and platelet lipoxidase activity. BW 755C was a much stronger inhibitor than KD compounds. The tested compounds stimulated oxygen consumption by cyclooxygenase from ram seminal vesicle microsomes in the presence of 100 microM of arachidonic acid in the range of concentrations between 30 and 300 microM and increased PGE2 generation in these experimental conditions. Radiochemical studies showed that BW 755C had been a stimulator of cyclooxygenase in higher (100 microM) substrate concentrations but, in agreement with a previous report it acted as an inhibitor of this enzyme when substrate concentration was 1.6 microM. Probably this component acted as a free radical scavenger.