title: Disturbance in hemoglobin metabolism and in vivo antimalarial activity of azole antimycotics.
abstract: Plasmodium parasites degrade host hemoglobin to obtain free amino acids, essential for protein synthesis. During this event, free toxic heme moieties crystallize spontaneously to produce a non-toxic pigment called hemozoin or ß-hematin. In this context, a group of azole antimycotics, clotrimazole (CTZ), ketoconazole (KTZ) and fluconazole (FCZ), were investigated for their abilities to inhibit ß-hematin synthesis (IßHS) and hemoglobin proteolysis (IHbP) in vitro. The ß-hematin synthesis was recorded by spectrophotometry at 405 nm and the hemoglobin proteolysis was determined by SDS-PAGE 12.5%, followed by densitometric analysis. Compounds were also assayed in vivo in a malaria murine model. CTZ and KTZ exhibited the maximal effects inhibiting both biochemical events, showing inhibition of β-hematin synthesis (IC50 values of 12.4 ± 0.9 µM and 14.4 ± 1.4 µM respectively) and inhibition of hemoglobin proteolysis (80.1 ± 2.0% and 55.3 ± 3.6%, respectively). There is a broad correlation to the in vivo results, especially CTZ, which reduced the parasitemia (%P) of infected-mice at 4th day post-infection significantly compared to non-treated controls (12.4 ± 3.0% compared to 26.6 ± 3.7%, p = 0.014) and prolonged the survival days post-infection. The results indicated that the inhibition of the hemoglobin metabolism by the azole antimycotics could be responsible for their antimalarial effect.
authors.affiliation: Unidad de Bioquímica, Facultad de Farmacia, Universidad Central de Venezuela, Apartado 47206, Los Chaguaramos, Caracas 1051-A, Venezuela. juanricardorodrigues@yahoo.es; neira.gamboa@ucv.ve
authors.forename: Juan Ricardo
authors.initials: JR
authors.lastname: Rodrigues
authors.forename: Diana
authors.initials: D
authors.lastname: Lourenco
authors.forename: Neira
authors.initials: N
authors.lastname: Gamboa
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D003022:Clotrimazole / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D015725:Fluconazole / Q000494:pharmacology*; D006420:Hemeproteins / Q000096:biosynthesis*; D006454:Hemoglobins / Q000187:drug effects / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D007654:Ketoconazole / Q000494:pharmacology*; D008288:Malaria / Q000097:blood / Q000188:drug therapy / Q000469:parasitology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010962:Plasmodium berghei / Q000187:drug effects* / Q000502:physiology
chemical_list: D000962:Antimalarials; D006420:Hemeproteins; D006454:Hemoglobins; C020753:hemozoin; D015725:Fluconazole; D003022:Clotrimazole; D007654:Ketoconazole