Аннотация:Intermittent fevers caused by Plasmodium parasites have been known for millennia, and have caused untold human suffering. Today, millions of people are afflicted by malaria each year, and hundreds of thousands die. Historically, the most successful synthetic antimalarial drug was chloroquine, as it was safe, inexpensive, and highly efficacious. However, plasmodial resistance to chloroquine now greatly limits its utility. Previously in our laboratories it has been shown that attachment of a "reversal agent moiety" to the side chain of chloroquine can result in the restoration of activity against chloroquine-resistant strains of P. falciparum malaria. In the first part of the work presented here, a study has been made of the importance of the quinoline ring substitution pattern to the activity of such reversed chloroquines. The compounds presented here include those bearing a substituent in the 2-, 5, 6-, 7-, and/or 8- position, and include those with chloro, bromo, iodo, fluoro, nitro, trifluoromethyl, methyl, and methoxy substituents. For reversed chloroquines, 2-, 5-, and 8- substituents have been found to decrease in vitro antiplasmodial activity against P. falciparum relative to 7-chloro substitution, whereas 6- and 7- substituted compounds with various substituents have in many cases similar activity to that of 7-chloro substituted compounds. Little difference has been observed between 6- and 7- substitution, or between chlorine and a methyl group in position 6. In most cases these effects on activity are directionally similar to those observed for chloroquine analogs without an attached reversal agent, but the magnitude of the effect is generally smaller, suggesting that the activities of reversed chloroquines are less affected by modifications to the quinoline ring system than is true for chloroquine analogs without an attached reversal agent.
