title: Sontochin as a guide to the development of drugs against chloroquine-resistant malaria.
abstract: Sontochin was the original chloroquine replacement drug, arising from research by Hans Andersag 2 years after chloroquine (known as "resochin" at the time) had been shelved due to the mistaken perception that it was too toxic for human use. We were surprised to find that sontochin, i.e., 3-methyl-chloroquine, retains significant activity against chloroquine-resistant strains of Plasmodium falciparum in vitro. We prepared derivatives of sontochin, "pharmachins," with alkyl or aryl substituents at the 3 position and with alterations to the 4-position side chain to enhance activity against drug-resistant strains. Modified with an aryl substituent in the 3 position of the 7-chloro-quinoline ring, Pharmachin 203 (PH-203) exhibits low-nanomolar 50% inhibitory concentrations (IC(50)s) against drug-sensitive and multidrug-resistant strains and in vivo efficacy against patent infections of Plasmodium yoelii in mice that is superior to chloroquine. Our findings suggest that novel 3-position aryl pharmachin derivatives have the potential for use in treating drug resistant malaria.
authors.affiliation: VA Medical Center, Portland, Oregon, USA.
authors.forename: Sovitj
authors.initials: S
authors.lastname: Pou
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Winter
authors.forename: Aaron
authors.initials: A
authors.lastname: Nilsen
authors.forename: Jane Xu
authors.initials: JX
authors.lastname: Kelly
authors.forename: Yuexin
authors.initials: Y
authors.lastname: Li
authors.forename: J Stone
authors.initials: JS
authors.lastname: Doggett
authors.forename: Erin W
authors.initials: EW
authors.lastname: Riscoe
authors.forename: Keith W
authors.initials: KW
authors.lastname: Wegmann
authors.forename: David J
authors.initials: DJ
authors.lastname: Hinrichs
authors.forename: Michael K
authors.initials: MK
authors.lastname: Riscoe
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use*; D002738:Chloroquine / Q000627:therapeutic use*; D004351:Drug Resistance; D020128:Inhibitory Concentration 50; D008288:Malaria / Q000188:drug therapy*; D051379:Mice; D015394:Molecular Structure; D010963:Plasmodium falciparum / Q000187:drug effects / Q000472:pathogenicity; D010967:Plasmodium yoelii / Q000187:drug effects / Q000472:pathogenicity
chemical_list: D000962:Antimalarials; D002738:Chloroquine