Role of human placental extract on succinic dehydrogenase activity in carrageenin-induced edema in rats in vivo and its effect on erythrocyte lysis, platelet aggregation and trypsin activity in vitro.

Significant increase of liver succinic dehydrogenase (SDH, EC 1.3.99.1) activity was produced by carrageenin-induced edema in rats. Pretreatment with human placental extract inhibited the increased liver SDH activity in a dose-dependent manner. Placental extract was found to have little or no effect on the liver SDH activity in normal rats. Furthermore, heat-induced erythrocyte lysis was inhibited to a substantial extent by the extract and was found to be dose-responsive. However, adenosine diphosphate (ADP)-induced platelet aggregation and trypsin activity were not changed by the placental extract in vitro. The study indicates that the membrane stabilization and depletion of adenosine triphosphate (ATP) synthesis may contribute to antiinflammatory effect of the extract.