Effect of cepharanthin on superoxide anion (O2-) production by macrophages.

Abstract

AbstractOur previous report showed the inhibitory action of cepharanthin on oxygen‐derived free radical production by polymorphonuclear leukocytes (PMN). In the present study, we examined the effects of cepharanthin on production of superoxide anion (O2–), one oxygen radical, by macrophages in vitro and in vivo.Phorbol myristate acetate‐induced O2– production by mouse peritoneal exudate cells (PEC), whose constituent cell types were identified as macrophages, lymphocytes, and PMN (75, 20, and less than 5%, respectively), was measured by ferricytochrome C reduction assay. Superoxide anion production by PEC, which depended mainly on the macrophage component, was inhibited 34% by 5 μg/ml cepharanthin and 85% by 50 μg/ml. These results indicate that cepharanthin suppresses O2– production by macrophages as well as by PMN. The fact that no inhibition of O2– by a xanthine‐xanthine oxidase system was observed indicates that cepharanthin is not a scavenger of O2–.Carrageenan‐induced paw edema is due to the activity of macrophages. Participation of O2– and other oxygen radicals is implicated in this edema, because the swelling is inhibited by administration of superoxide dismutase. The effects of cepharanthin on O2– production by macrophages was examined using this experimental system in mice. However, no significant inhibition of the edema by cepharanthin was observed.