Antitrichomonal action of emodin in mice.

Emodin, an active component contained in the root and rhizome of Rheum palmatum L. (Polygonaceae), was found to have an inhibitory effect on the pathogenicity of Trichomonas vaginalis in mice. Emodin delayed the development of subcutaneous abscesses due to infection of this parasite. Also, it cures the intravaginal infection of trichomonads through oral administration. In cell cultures, it reduced the cytotoxic effect of this parasite towards mammalian cells. This inhibition was markedly reversed by the coexistence of free radical scavengers, indicating the possible mediation of free radicals.