Anti-inflammatory and platelet anti-aggregant activity of phospholipase-A2 inhibitors

Mepacrine, papaverine, p-bromophenacyl bromide and 2,3-dibromo(4'-cyclohexyl-3'-chloro)-phenyl-4-oxo-butyric acid (CB 874) inhibit the hydrolysis of phospholipids induced by thrombin in dog platelets. They also exhibit anti-inflammatory and anti-aggregant properties. These biological activities may be explained by a direct or indirect inhibitory action on phospholipase A2. Phospholipase A2 inhibitors may block not only the release of arachidonic acid and its subsequent conversion into prostaglandins but also the formation of lysophospholipids involved in inflammation and/or platelet aggregation.