Coumarin or warfarin treatment of mice does not increase the microbicidal or tumoricidal capacities of macrophages.

Benzopyrones have been shown to affect several functions of macrophages. We examined the effects of two benzopyrones, coumarin and warfarin, on the capacity of mouse macrophages to inhibit microorganisms and tumour target cells. Mice were treated with daily i.v. doses of either drug. Then the mice were challenged with lethal doses of Toxoplasma gondii or peritoneal macrophages from these mice were challenged in vitro with T. gondii or tumour target cells Survival of coumarin or warfarin-treated mice challenged with T. gondii was similar to that of control mice. Multiplication of T gondii and growth of tumour target cells were similar in preparations of macrophages from coumarin-treated, warfarin-treated, or control mice and were inhibited in preparations of activated macrophages from Corynebacterium parvum-treated mice that served as positive controls. Under our experimental conditions, benzopyrones did not activate mouse macrophages.