Navegando por Autor "Taranto, Alex Gutterres"
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Item Detection of the antiviral activity of epicatechin isolated from Salacia crassifolia (Celastraceae) against Mayaro virus based on protein C homology modelling and virtual screening.(2018) Ferreira, Priscila Gonçalves; Ferraz, Ariane Coelho; Figueiredo, Jenyfer Emanuelle; Lima, Caroline Ferrante; Rodrigues, Vanessa Gregório; Taranto, Alex Gutterres; Ferreira, Jaqueline Maria Siqueira; Brandão, Geraldo Célio; Vieira Filho, Sidney Augusto; Duarte, Lucienir Pains; Magalhães, Cíntia Lopes de Brito; Magalhães, José Carlos deMayaro fever, caused by Mayaro virus (MAYV) is a sub-lethal disease with symptoms that are easily confused with those of dengue fever, except for polyarthralgia, which may culminate in physical incapacitation. Recently, outbreaks of MAYV have been documented in metropolitan areas, and to date, there is no therapy or vaccine available. Moreover, there is no information regarding the three-dimensional structure of the viral proteins of MAYV, which is important in the search for antivirals. In this work, we constructed a three-dimensional model of protein C of MAYV by homology modelling, and this was employed in a manner similar to that of receptors in virtual screening studies to evaluate 590 molecules as prospective antiviral agents. In vitro bioassays were utilized to confirm the potential antiviral activity of the flavonoid epicatechin isolated from Salacia crassifolia (Celastraceae). The virtual screening showed that six flavonoids were promising ligands for protein C. The bioassays showed potent antiviral action of epicatechin, which protected the cells from almost all of the effects of viral infection. An effective concentration (EC50) of 0.247 μmol/mL was observed with a selectivity index (SI) of 7. The cytotoxicity assay showed that epicatechin has low toxicity, with a 50% cytotoxic concentration (CC50) greater than 1.723 µmol/mL. Epicatechin was found to be twice as potent as the reference antiviral ribavirin. Furthermore, a replication kinetics assay showed a strong inhibitory effect of epicatechin on MAYV growth, with a reduction of at least four logs in virus production. Our results indicate that epicatechin is a promising candidate for further testing as an antiviral agent against Mayaro virus and other alphaviruses.Item Synthesis, cytotoxic activity, and mode of action of new Santacruzamate A analogs.(2018) Andrade, Silmara Nunes; Evangelista, Fernanda Cristina Gontijo; Seckler, Diego Eduardo Lima; Marques, Deisielly Ribeiro; Freitas, Tulio Resende; Nunes, Renata Rachide; Oliveira, Júlia Teixeira de; Ribeiro, Rosy Iara Maciel de Azambuja; Santos, Helio Batista dos; Thomé, Ralph Gruppi; Taranto, Alex Gutterres; Santos, Fabio Vieira dos; Viana, Gustavo Henrique Ribeiro; Freitas, Rossimiriam Pereira de; Humberto, Jorge Luiz; Sabino, Adriano de PaulaBreast and ovarian cancer are the most common cancers in women. Available cancer treatments, in general, have limited efficacy and frequent, undesirable side effects. Recently, scientists have focused on searching for new epigenetic modulators such as inhibitors of DNA methyltransferases and histone deacetylases (HDACs), with novel properties and selectivity. We report the synthesis of seven new analogs of Santacruzamate A. Molecular modeling showed that compounds 3–9 presented the best binding energies (kcal/mol) against HDAC4 compared to that of crystallographic ligand. The compounds were evaluated against MCF-7 and MDA-MB-231 (breast cancer), TOV-21G (ovarian adenocarcinoma), and WI-26VA4 (non-tumor lung fibroblasts) cells. Compound 5, the most potent and selective of the series, exhibited remarkably enhanced anticancer potency, with IC50 values for the tumor cells of 24.3–44.93 μM, compared with that of etoposide (12–18.57 μM) and doxorubicin (2.1–4.37 μM). Further investigation showed that compound 5 could promote DNA damage, increase the activity of caspases-3 and -9, and upregulate mRNA levels of p21, TP53, and BAK, suggesting apoptotic cell death of the tumor cells via the intrinsic pathway. This study demonstrated that synthetic analogs of santacruzamate A with zinc-linked groups are effective for improving both HDAC inhibition and antitumor activity.