title: Cell death and ultrastructural alterations in Leishmania amazonensis caused by new compound 4-Nitrobenzaldehyde thiosemicarbazone derived from S-limonene.
abstract: BACKGROUND
  The treatment of leishmaniasis with pentavalent antimonials is problematic because of their toxicity. Investigations of potentially active molecules are important to discover less toxic drugs that are viable economic alternatives for the treatment of leishmaniasis. Thiosemicarbazones are a group of molecules that are known for their wide versatility and biological activity. In the present study, we examined the antileishmania activity, mechanism of action, and biochemical alterations produced by a novel molecule, 4-nitrobenzaldehyde thiosemicarbazone (BZTS), derived from S-limonene against Leishmania amazonensis.
  
  
  RESULTS
  BZTS inhibited the growth of the promastigote and axenic amastigote forms, with an IC50 of 3.8 and 8.0 μM, respectively. Intracellular amastigotes were inhibited by the compound with an IC50 of 7.7 μM. BZTS also had a CC50 of 88.8 μM for the macrophage strain J774A1. BZTS altered the shape, size, and ultrastructure of the parasites, including damage to mitochondria, reflected by extensive swelling and disorganization of the inner mitochondrial membrane, intense cytoplasmic vacuolization, and the presence of concentric membrane structures inside the organelle. Cytoplasmic lipid bodies, vesicles inside vacuoles in the flagellar pocket, and enlargement were also observed. BZTS did not induce alterations in the plasma membrane or increase annexin-V fluorescence intensity, indicating no phosphatidylserine exposure. However, it induced the production of mitochondrial superoxide anion radicals.
  
  
  CONCLUSIONS
  The present results indicate that BZTS induced dramatic effects on the ultrastructure of L. amazonensis, which might be associated with mitochondrial dysfunction and oxidative damage, leading to parasite death.
authors.forename: Elizandra Aparecida
authors.initials: EA
authors.lastname: Britta
authors.forename: Débora Botura
authors.initials: DB
authors.lastname: Scariot
authors.forename: Hugo
authors.initials: H
authors.lastname: Falzirolli
authors.forename: Tânia
authors.initials: T
authors.lastname: Ueda-Nakamura
authors.forename: Cleuza Conceição
authors.initials: CC
authors.lastname: Silva
authors.forename: Benedito Prado Dias
authors.initials: BP
authors.lastname: Filho
authors.forename: Redouane
authors.initials: R
authors.lastname: Borsali
authors.forename: Celso Vataru
authors.initials: CV
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001547:Benzaldehydes / Q000302:isolation & purification / Q000494:pharmacology*; D016923:Cell Death; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D053138:Cyclohexenes / Q000737:chemistry*; D020128:Inhibitory Concentration 50; D007894:Leishmania mexicana / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D000077222:Limonene; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D015388:Organelles / Q000187:drug effects / Q000648:ultrastructure; D021261:Parasitic Sensitivity Tests; D013729:Terpenes / Q000737:chemistry*; D013882:Thiosemicarbazones / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000981:Antiprotozoal Agents; D001547:Benzaldehydes; D053138:Cyclohexenes; D013729:Terpenes; D013882:Thiosemicarbazones; C029915:4-nitrobenzaldehyde; D000077222:Limonene