EFFECTS OF SYNTHETIC HYDROXY ISOTHIOCYANATES ON MICROBIAL SYSTEMS

Hydroxy isothiocyanates (ITCs), including some new derivatives of natu rally occurring compounds, were synthesized and their minimum inhibito ry, minimum fungicidal, and minimum bactericidal concentrations for As pergillus niger, Aspergillus fumigatus, Staphylococcus aureus, and Esc herichia coli were estimated. These compounds were strongly antimicrob ial; for example, 2-(4-hydroxyphenyl) ethyl ITC inhibited growth of al l strains examined at concentrations of 7.8 to 15.6 mu g/ml. The ATP c oncentration in E. coli was markedly reduced when cells were treated w ith 2-(4-hydroxyphenyl)ethyl ITC. Inhibition of the growth of E. coli by 2-(4-hydroxyphenyl)ethyl ITC was decreased in the presence of cyste ine. Streptolysin S production in washed cells of Streptococcus equisi milis was extremely sensitive to this ITC derivative and this inhibiti on also was counteracted by cysteine. The results showed that the ITC compounds had antimicrobial effects by blocking sulfhydryl groups.