Synthesis of New 4-Aminoquinolines and Evaluation of Their In Vitro Activity against Chloroquine-Sensitive and Chloroquine-Resistant Plasmodium falciparum
作者:Chandima S. K. Rajapakse、Maryna Lisai、Christiane Deregnaucourt、Véronique Sinou、Christine Latour、Dipankar Roy、Joseph Schrével、Roberto A. Sánchez-Delgado
DOI:10.1371/journal.pone.0140878
日期:——
The efficacy of chloroquine, once the drug of choice in the fight against Plasmodium falciparum, is now severely limited due to widespread resistance. Amodiaquine is one of the most potent antimalarial 4-aminoquinolines known and remains effective against chloroquine-resistant parasites, but toxicity issues linked to a quinone-imine metabolite limit its clinical use. In search of new compounds able to retain the antimalarial activity of amodiaquine while circumventing quinone-imine metabolite toxicity, we have synthesized five 4-aminoquinolines that feature rings lacking hydroxyl groups in the side chain of the molecules and are thus incapable of generating toxic quinone-imines. The new compounds displayed high in vitro potency (low nanomolar IC50), markedly superior to chloroquine and comparable to amodiaquine, against chloroquine-sensitive and chloroquine-resistant strains of P. falciparum, accompanied by low toxicity to L6 rat fibroblasts and MRC5 human lung cells, and metabolic stability comparable or higher than that of amodiaquine. Computational studies indicate a unique mode of binding of compound 4 to heme through the HOMO located on a biphenyl moeity, which may partly explain the high antiplasmodial activity observed for this compound.
氯喹曾是抗击恶性疟原虫的首选药物,但由于抗药性广泛存在,其疗效现已受到严重限制。阿莫地喹是已知最有效的 4-氨基喹啉类抗疟药物之一,对耐氯喹的寄生虫仍然有效,但与醌-亚胺代谢物有关的毒性问题限制了它在临床上的使用。为了寻找既能保留阿莫地喹的抗疟活性,又能避免醌-亚胺代谢物毒性的新化合物,我们合成了五种 4-氨基喹啉类化合物,这些化合物的分子侧链中缺少羟基环,因此无法生成有毒的醌-亚胺。这些新化合物对氯喹敏感和抗氯喹的恶性疟原虫菌株显示出较高的体外效力(低纳摩尔 IC50),明显优于氯喹,与阿莫地喹相当,同时对 L6 大鼠成纤维细胞和 MRC5 人类肺细胞毒性较低,代谢稳定性与阿莫地喹相当或高于阿莫地喹。计算研究表明,化合物 4 通过位于联苯态的 HOMO 与血红素结合,具有独特的模式,这可能是该化合物具有较高抗疟活性的部分原因。