title: Synthesis and biological evaluation of fluorescent leishmanicidal analogues of hexadecylphosphocholine (miltefosine) as probes of antiparasite mechanisms.
abstract: The leishmanicidal mechanism of miltefosine (hexadecylphosphocholine, MT) is not clearly understood. Valuable insights into its mode of action could be obtained by fluorescence techniques, given suitably emitting analogues. In this regard, the synthesis and biological characterization of two fully competent MT fluorescent analogues is reported here: all-(E)-13-phenyltrideca-6,8,10,12-tetraenylphosphocholine (PTE-MT) and all-(E)-13-phenyltrideca-8,10,12-trien-6-ynylphosphocholine (PTRI-MT). Both compounds show large absorption coefficients and a modest, but usable, fluorescence yield. Their activities were very similar to that of MT and were recognized by the MT uptake system of Leishmania. Their localization in living L. donovani promastigotes by confocal microscopy show a homogeneous intracellular distribution of the fluorescence. The concentration of PTRI-MT within the parasites (ca. 1.7 mM) showed a 100-fold enrichment relative to its external concentration. These results are consistent with a multiple target leishmanicidal mechanism for MT and validate the application of these analogues for pharmacokinetic and diagnostic studies concerning the chemotherapy of leishmaniasis.
authors.affiliation: Centro de Investigaciones Biológicas, C.S.I.C., Ramiro de Maeztu 9, E-28040 Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Saugar
authors.forename: Javier
authors.initials: J
authors.lastname: Delgado
authors.forename: Valentín
authors.initials: V
authors.lastname: Hornillos
authors.forename: Juan R
authors.initials: JR
authors.lastname: Luque-Ortega
authors.forename: Francisco
authors.initials: F
authors.lastname: Amat-Guerri
authors.forename: A Ulises
authors.initials: AU
authors.lastname: Acuña
authors.forename: Luis
authors.initials: L
authors.lastname: Rivas
mesh_terms: D000818:Animals; D004351:Drug Resistance; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D007893:Leishmania donovani / Q000187:drug effects* / Q000378:metabolism; D018613:Microscopy, Confocal; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014344:Trypanocidal Agents / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology
chemical_list: C526811:13-phenyltrideca-6,8,10,12-tetraenylphosphocholine; C526812:13-phenyltrideca-8,10,12-trien-6-ynylphosphocholine; D005456:Fluorescent Dyes; D014344:Trypanocidal Agents; D010767:Phosphorylcholine; C039128:miltefosine