Inhibitory effects of organic sulfur compounds on Histoplasma capsulatum

Eight classes of organic sulfur compounds, comprising 42 substances, were tested in vitro for activity against the yeast phase ofHistoplasma capsulatum Darling. Activity was found in the classes of thiols, thio acids, disulfides, and thiolsulfonates. The classes of sulfinates, sulfenamides, penicillamine analogs, and reaction products of thiols with aldehydes or ketones were unpromising. Tentative conclusions are drawn of structure-activity relations within classes as a guide to coupling of classes to form disulfides.