Effect on Biological Activity of Substituting Sulphur for Oxygen in an Organic Arsenical Compound.

Abstract

Voegtlin and his associates' have called attention to the sipificance of sulphur metabolism in connection with arsenic toxicity. It seemed of interest to determine the effect on biological activity of substituting sulphur for oxygen in an organic arsenical compound where this substitution is possible. We approached this problem from our particular standpoint of the chemotherapy of amebiasis, determining toxicity on oral administration to cats and rabbits, and amebacidal activity in vitro on Entavneba histolytica, employing technique described elsewhere,' except that we used a Musgrave-Clegg slant and Ringer's solution containing albumen and rice-starch with pH adjusted to lie between 7.4 and 7.6, in an effort to prevent absorption of the drug by the solid medium.Through the courtesy of the Lilly Research Laboratories, we secured 4-carbaminophenyl-arsonic acid ( H,0,As.CsH,.NHCONH2) and 4-thiocarbamino-phenyl-arsonic acid ( H,0,As.CsH4.NHCS-NH,), which differ from each other in that the latter contains sul-* LiUy Research Fellow.