The value of multifactorial screening for anti-inflammatory activity as shown by coumarin.

Different types of acute inflammatory pleural reactions have been used as a means of detecting the anti-inflammatory potential of a particular drug coumarin. The latter had some type of activity in all the reactions. However, whereas coumarin inhibited leucocyte accumulation induced by dextran it had no effect on the volume of fluid exudate. Conversely, coumarin reduced the volume of exudate in the Arthus reaction whereas the cellular infiltrate remained unaltered. Leucocytes from dextran-induced exudate (predominantly polymorphs) removed from animals pretreated with coumarin showed marked inhibition of migration in vitro. This correlated well with the suppression by coumarin of the dextran-induced leucocyte response in vivo. Coumarin administered in vivo was also shown to stimulate phagocytosis of latex by mouse peritoneal macrophages in vitro. These findings are discussed with respect to the evaluation of anti-inflammatory drug activity and to the mode of action of coumarin.