EFFECT OF NAPHTHOQUINONES ON SCHISTOSOMA MANSONI IN VITRO AND IN VIVO

¹ Department of Pharmacology, School of Medicine, Western Reserve University, Cleveland, Ohio

1. A number of naphthoquinones were found to inhibit glycolysis of adult Schistosoma mansoni in low concentrations. The relationship between structural characteristics and antiglycolytic activity has been studied.

2. The antiglycolytic activity of these compounds against S. mansoni is markedly reduced in the presence of serum.

3. The chemotherapeutic activity of naphthoquinones against S. mansoni in mice is of a very low order and cannot be demonstrated when these compounds are administered alone. Some of them, e.g., 2-methyl-1,4-naphthoquinone, enhance slightly the chemotherapeutic effect of organic antimonials. This synergism is considered to be of a magnitude insufficient to warrant clinical trial.

4. The results obtained indicate that naphthoquinones inhibit glycolysis of S. mansoni by a mechanism different from those which produce inhibition of respiration of malaria parasites and of snails, of the activity of brain choline acetylase and of the glycolysis of mammalian tissues and of T. equiperdum. Furthermore, inactivation of sulfhydryl groups does not appear to explain the antiglycolytic effect of naphthoquinones against schistosomes.