Abstract
In a paper on the “Toxic Action of Opium Alkaloids Individually and in Combination with Each Other on Paramecia,” by Macht and Fisher, 1 it was shown that some of the opium alkaloids were very toxic for that organism while others produced very little effect on it. It was found that the benzyl-isoquinolin group of alkaloids of which papaverin is the principal representative killed paramecia very quickly; whereas the pyridinphenanthrene group of which morphin is the principal member was comparatively non-toxic. A further analysis of the papaverin action proved that the toxicity of that alkaloid was to be ascribed to the presence of the benzyl radicle in its molecule. Following the above investigation, it was interesting to inquire into whether the opium alkaloids are also toxic for other forms of protozoa, and especially for trypanosomes. The present authors have accordingly undertaken the study of the action of various opium alkaloids and their derivatives on Trypanosoma brucei. The organisms were obtained through the kindness of Dr. Wade Brown, of the Rockefeller Institute for Medical Research.
Experiments in vitro revealed as in the case of paramecia that the papaverin group of opium alkaloids was very toxic for trypanosomes. Papaverin itself in dilutions of 1 to 10,000 markedly inhibited the movements of the organisms in a few minutes and killed them completely within thirty minutes. Similarly the alkaloids narcotin and narcein were also found to be very toxic for trypanosomes in vitro.
Contrary to expectations however the morphin group of alkaloids while not as toxic as papaverin was also found to be deleterious to the trypanosomes, but in a much lesser degree. Dilutions of morphin sulphate 1 to 2,000 did not kill the organisms within an hour but were found to inhibit slightly their movements after the lapse of some ten minutes.
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