Giardia duodenalis is an ubiquitous parasitic pathogen that causes significant morbidity and mortality worldwide. Failures in drug therapy are commonly due to poor patient compliance as a result of the need for repeated administration, off target drug effects and increasing parasite drug resistance. In this study the in vitro efficacy and selectivity of the aminoguanidine compound robenidine and 2 structural analogues against Giardia were determined. After 5 h exposure to each compound the IC50 was as low as 0.2 μM with corresponding MLCs as low as 2.8 μM. This is in contrast to metronidazole which required 24 h to exhibit inhibitory activity. A modified adherence assay, developed for this study, demonstrated that three of the compounds inhibited in vitro adherence of the parasite. The lead compound exhibited rapid giardicidal activity (<5hr). In addition, microscopy studies demonstrated damage to the plasma membrane of trophozoites. In conclusion, a class of aminoguanidines, represented by robenidine, has shown antigiardial activity warranting further investigation.

中文翻译：

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氨基胍：治疗十二指肠感染的新线索。

贾第鞭毛虫（Giardia duodenalis）是一种普遍存在的寄生性病原体，在世界范围内引起大量发病和死亡。药物治疗失败通常是由于需要重复给药，脱靶药物作用和增加的寄生虫耐药性导致患者依从性差。在这项研究中，测定了氨基胍化合物罗苯尼定和2种结构类似物对贾第鞭毛虫的体外功效和选择性。暴露于每种化合物5小时后，IC50低至0.2μM，相应的MLC低至2.8μM。这与甲硝唑需要24小时才能表现出抑制活性相反。为该研究开发的改良的粘附试验表明，其中三种化合物抑制了寄生虫的体外粘附。铅化合物表现出快速的杀菌作用（<5小时）。此外，显微镜研究表明滋养体质膜受损。总之，一类以罗苯尼定为代表的氨基胍类药物已显示出抗真菌活性，值得进一步研究。