The Action of Ipecacuanha Alkaloids on Entamoeba histolytica and some other Entozoic Amoebae in Culture

Abstract

It is now recognized, by all competent observers, that emetine is a specific therapeutic agent for the treatment of amoebic dysentery; but although it is known that a thorough course of emetine, in some form, will eradicate an infection with Entamoeba histolytica from most human beings, there is still complete ignorance as to how the cure is effected. The obvious hypothesis, that emetine is a specific poison for E. histolytica, has not hitherto been supported by adequate experimental evidence. It is true that observers have described experiments in which the alkaloid, in high dilution, has apparently killed various amoebae in vitro; but these experiments either ignored the peculiarly specific action of emetine in vivo on E. histolytica, or were carried out without adequate controls.

Chemotherapy of Amebiasis

“…Thus Dobell and Laidlaw (1926b) found emetine and cephaeline to be more active than isoemetine, demethoxyemetine, noremetine, psychotrine, or methylpsychotrine in vitro. Structure and activity.…”

“…As the acute oral LD 5 0 for mice was greater than l 6 g . Ganatra et al, 1956;Donckaster et al, 1959). , Mantomide appeared to offer a high therapeutic ratio.…”

Provocative Emetine in Diagnosis of Amoebiasis

“…However, Lawrence (1946) and Wenyon (1947) thought this method to be irrational and based on a mistaken analogy with the provocative dose of neoarsphenamine in serological diagnosis of syphilis. Dobell and Laidlaw (1926) reported that, in liquid medium, 1 in 5,000,000 of emetine hydrochloride was lethal to E. histolytica. The mode of amoebicidal action of emetine hydrochloride is not well known.…”

Nutrition and Physiology of Endamoeba Histolytica

“…Occasionally, survival of amebas over a prolonged period of time is confused with growth. Drbohlav (32) suggested using blood agar covered with Ringer-egg white which was buffered and adjusted to a pH of 7.4. In England, Dobell and Laidlaw (30,31) also modified the Boeck-Drbohlav medium. They added starch to the cultures, stating that starch particles can be ingested by the amebas, thus supplying an abundant carbohydrate source (the role of starch is discussed in section II, part 2).…”

“…Laidlaw (30,31) first introduced starch into the ameba cultures, stating that starch particles could be ingested by the amebas as a carbohydrate source. They also stated that the amebas lived longer in Boeck-Drbohlav medium with added starch than in the original medium containing glucose as the latter can be fermented readily by the bacteria, producing acid which made the medium unsuitable for amebic growth.…”