Growth inhibition of axenic Entamoeba histolytica by tubercidin and ara-A.

Several analogs of nucleic acid components including 7-deazaadenosine (tubercidin), adenine 9-beta-D-arabinofuranoside (ara-A), 8-azaguanine, 6-azathymine, 6-mercaptopurine, 6-mercaptopurine arabinoside, 6-mercaptopurine riboside and 1,3-dideazapurine (benzimidazole) were tested for inhibition of growth of an axenic strain of Entamoeba histolytica in 72 hour experiments. Metronidazole and emetine were included in the experiments for comparison. Tubercidin and ara-A, analogs of adenosine, were the most potent of the tested growth inhibitors with amebistatic concentrations of about 0.6 and 3.0 microM, respectively. The other analogs did not significantly inhibit amebal growth below 100 microM. In the present study metronidazole and emetine had amebistatic concentrations, respectively, 17- and 60-fold higher than tubercidin.