[The action of benzydamine on phospholipase activation]

The effects of the antiinflammatory drug benzydamine (Tantum) on phospholipase activities were determined in vitro, employing various enzyme preparations (rat liver plasma membranes, endoplasmic reticulum, lysosomes; human seminal plasma) and stereospecifically radiolabeled phosphatidylethanolamines as substrates. Fatty acid release from the sn-2 position was inhibited at drug concentrations above 10(-5) mol/l. Concerning the mode of inhibition, a mixed type was found for the soluble phospholipase A2. Impaired fatty acid release from the sn-2 position might contribute to the mechanism of antiinflammatory action of benzydamine by rendering less free precursor acid available for the synthesis of eicosanoids. Fatty acid release from the sn-1 position was inhibited at benzydamine concentrations from 10(-6)-10(-2) mol/l only in lysosomes, whereas in plasma membranes and endoplasmic reticulum it was stimulated, maximally (at 10(-3) mol/l) about 25% and 50%, respectively.