title: 4-amino bis-pyridinium derivatives as novel antileishmanial agents.
abstract: The antileishmanial activity of a series of bis-pyridinium derivatives that are analogues of pentamidine have been investigated, and all compounds assayed were found to display activity against promastigotes and intracellular amastigotes of Leishmania donovani and Leishmania major, with 50% effective concentrations (EC50s) lower than 1 μM in most cases. The majority of compounds showed similar behavior in both Leishmania species, being slightly more active against L. major amastigotes. However, compound VGP-106 {1,1'-(biphenyl-4,4'-diylmethylene)bis[4-(4-bromo-N-methylanilino)pyridinium] dibromide} exhibited significantly higher activity against L. donovani amastigotes (EC50, 0.86 ± 0.46 μM) with a lower toxicity in THP-1 cells (EC50, 206.54 ± 9.89 μM). As such, VGP-106 was chosen as a representative compound to further elucidate the mode of action of this family of inhibitors in promastigote forms of L. donovani. We have determined that uptake of VGP-106 in Leishmania is a temperature-independent process, suggesting that the compound crosses the parasite membrane by diffusion. Transmission electron microscopy analysis showed a severe mitochondrial swelling in parasites treated with compound VGP-106, which induces hyperpolarization of the mitochondrial membrane potential and a significant decrease of intracellular free ATP levels due to the inhibition of ATP synthesis. Additionally, we have confirmed that VGP-106 induces mitochondrial ROS production and an increase in intracellular Ca(2+) levels. All these molecular events can activate the apoptotic process in Leishmania; however, propidium iodide assays gave no indication of DNA fragmentation. These results underline the potency of compound VGP-106, which may represent a new avenue for the development of novel antileishmanial compounds.
authors.affiliation: Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Universidad de Granada, Granada, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: Gómez-Pérez
authors.affiliation: Instituto de Parasitología y Biomedicina "López-Neyra," IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Armilla, Granada, Spain.
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Manzano
authors.affiliation: Instituto de Parasitología y Biomedicina "López-Neyra," IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Armilla, Granada, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: García-Hernández
authors.affiliation: Instituto de Parasitología y Biomedicina "López-Neyra," IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Armilla, Granada, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Castanys
authors.affiliation: Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Universidad de Granada, Granada, Spain.
authors.forename: Joaquín M
authors.initials: JM
authors.lastname: Campos Rosa
authors.affiliation: Instituto de Parasitología y Biomedicina "López-Neyra," IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Armilla, Granada, Spain gamarro@ipb.csic.es.
authors.forename: Francisco
authors.initials: F
authors.lastname: Gamarro
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000981:Antiprotozoal Agents / Q000494:pharmacology; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002797:Choline Kinase / Q000037:antagonists & inhibitors; D006801:Humans; D007893:Leishmania donovani / Q000187:drug effects*; D018320:Leishmania major / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D008933:Mitochondrial Swelling / Q000187:drug effects*; D021261:Parasitic Sensitivity Tests; D010419:Pentamidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000981:Antiprotozoal Agents; D017382:Reactive Oxygen Species; D010419:Pentamidine; D000255:Adenosine Triphosphate; D002797:Choline Kinase; D002118:Calcium