title: The Effectiveness of Natural Diarylheptanoids against Trypanosoma cruzi: Cytotoxicity, Ultrastructural Alterations and Molecular Modeling Studies.
abstract: Curcumin (CUR) is the major constituent of the rhizomes of Curcuma longa and has been widely investigated for its chemotherapeutic properties. The well-known activity of CUR against Leishmania sp., Trypanosoma brucei and Plasmodium falciparum led us to investigate its activity against Trypanosoma cruzi. In this work, we tested the cytotoxic effects of CUR and other natural curcuminoids on different forms of T. cruzi, as well as the ultrastructural changes induced in epimastigote form of the parasite. CUR was verified as the curcuminoid with more significant trypanocidal properties (IC50 10.13 μM on epimastigotes). Demethoxycurcumin (DMC) was equipotent to CUR (IC50 11.07 μM), but bisdemethoxycurcumin (BDMC) was less active (IC50 45.33 μM) and cyclocurcumin (CC) was inactive. In the experiment with infected murine peritoneal macrophages all diarylheptanoids were more active than the control in the inhibition of the trypomastigotes release. The electron microscopy images showed ultrastructural changes associated with the cytoskeleton of the parasite, indicating tubulin as possible target of CUR in T. cruzi. The results obtained by flow cytometry analysis of DNA content of the parasites treated with natural curcuminoids suggested a mechanism of action on microtubules related to the paclitaxel`s mode of action. To better understand the mechanism of action highlighted by electron microscopy and flow cytometry experiments we performed the molecular docking of natural curcuminoids on tubulin of T. cruzi in a homology model and the results obtained showed that the observed interactions are in accordance with the IC50 values found, since there CUR and DMC perform similar interactions at the binding site on tubulin while BDMC do not realize a hydrogen bond with Lys163 residue due to the absence of methoxyl groups. These results indicate that trypanocidal properties of CUR may be related to the cytoskeletal alterations.
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Vitor
authors.initials: V
authors.lastname: Sueth-Santiago
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Veterinária, Departamento de Microbiologia e Imunologia Veterinária, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Julliane de B B
authors.initials: JB
authors.lastname: Moraes
authors.affiliation: Laboratório de Biologia Parasitária, Centro de Pesquisas Gonçalo Moniz (CPqGM-Fiocruz), Rua Waldemar Falcão, 121, Candeal, CEP: 40.296-710, Salvador, BA, Brazil.
authors.forename: Eliomara Sousa
authors.initials: ES
authors.lastname: Sobral Alves
authors.affiliation: Laboratório de Biologia Parasitária, Centro de Pesquisas Gonçalo Moniz (CPqGM-Fiocruz), Rua Waldemar Falcão, 121, Candeal, CEP: 40.296-710, Salvador, BA, Brazil.
authors.forename: Marcos André
authors.initials: MA
authors.lastname: Vannier-Santos
authors.affiliation: Universidade Federal do Rio de Janeiro, Instituto de Biofísica Carlos Chagas Filho, Ilha do Fundão, Cidade Universitária, CEP: 21.941-902, Rio de Janeiro, RJ, Brazil.
authors.forename: Célio G
authors.initials: CG
authors.lastname: Freire-de-Lima
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Rosane N
authors.initials: RN
authors.lastname: Castro
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Gustavo Peron
authors.initials: GP
authors.lastname: Mendes-Silva
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Matemática, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Catarina de Nigris
authors.initials: CN
authors.lastname: Del Cistia
authors.affiliation: Laboratório de Química Medicinal e Computacional, Centro de Pesquisa e Inovação em Biodiversidade e Fármacos, Instituto de Física de São Carlos, Universidade de São Paulo, CP 396, CEP: 13.560-970, São Carlos, SP, Brazil.
authors.forename: Luma Godoy
authors.initials: LG
authors.lastname: Magalhães
authors.affiliation: Laboratório de Química Medicinal e Computacional, Centro de Pesquisa e Inovação em Biodiversidade e Fármacos, Instituto de Física de São Carlos, Universidade de São Paulo, CP 396, CEP: 13.560-970, São Carlos, SP, Brazil.
authors.forename: Adriano Defini
authors.initials: AD
authors.lastname: Andricopulo
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Carlos Mauricio R
authors.initials: CM
authors.lastname: Sant Anna
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Veterinária, Departamento de Microbiologia e Imunologia Veterinária, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Debora
authors.initials: D
authors.lastname: Decoté-Ricardo
authors.affiliation: Universidade Federal Rural do Rio de Janeiro, Instituto de Ciências Exatas, Departamento de Química, BR 465, Km 07, CEP: 23.890-000, Seropédica, RJ, Brazil.
authors.forename: Marco Edilson
authors.initials: ME
authors.lastname: Freire de Lima