Browsing by Author "Torchelsen, Fernanda Karoline Vieira da Silva"

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    Antileishmanial activity of compounds produced by endophytic fungi derived from medicinal plant Vernonia polyanthes and their potential as source of bioactive substances.
    (2015) Nascimento, Adriana Mendes do; Soares, Mateus Gonçalves; Torchelsen, Fernanda Karoline Vieira da Silva; Araújo, Jorge Augusto Viana de; Lage, Paula Souza; Duarte, Mariana Costa; Andrade, Pedro Henrique Rocha de; Ribeiro, Tatiana Gomes; Coelho, Eduardo Antônio Ferraz; Nascimento, Andréa Mendes do
    The purpose of this work was to evaluate the antileishmanial activity of endophytic fungi isolated from leaves of Vernonia polyanthes plant and their prospective use in the discovery of bioactive compounds. Sixteen endophytes were isolated by using potato dextrose agar medium and submitted to cultivation in rice medium. The fungal cultures were extracted with ethanol and used as crude extracts for testing their antileishmanial activity. The most active ethanol extract was obtained from P2-F3 strain, which was identified as Cochliobolus sativus by ITS rRNA gene sequence data. Followed by a bioassay-guided fractionation, the cochlioquinone A, isocochlioquinone A and anhydrocochlioquinone A compounds were isolated from the crude extracts and demonstrated to inhibit the parasites. From the present work, it is possible to conclude that endophytic fungi derived from medicinal plant V. polyanthes may be considered promising source for the discovery of bioactive compounds.
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    Avaliação da atividade anti-Trypanosoma cruzi in vitro e in vivo do composto silibinina isolado e associado ao benznidazol.
    (2019) Torchelsen, Fernanda Karoline Vieira da Silva; Lana, Marta de; Silva, Glenda Nicioli da; Murta, Silvane Maria Fonseca; Brandão, Geraldo Célio; Lana, Marta de
    A doença de Chagas (DC) é uma doença parasitária endêmica na América Latina e encontrada em diversos países no mundo. Seu tratamento é feito com o benznidazol (BZ) e o nifurtimox (NF), ambos fármacos com baixa eficácia terapêutica na maoria dos pacientes em fase crônica tardia da DC, e que causam vários efeitos colaterais. A busca por novos fármacos para a DC é estimulada entre produtos naturais e em estratégias como associação de fármacos. A silibinina (SLB) é um composto natural capaz de inibir a proteína de efluxo (Pgp) nas membranas celulares, induzir a morte de microrganismos, além de possuir atividade anti-inflamatória. Ainda não há na literatura relato de sua atividade em T. cruzi. Neste trabalho foi avaliada a atividade in vitro e in vivo de SLB e de SLB associada a BZ (SLB+BZ) frente a cepa Y de T. cruzi. Foi realizado ensaio de citotoxicidade pelo método de MTT em células VERO (24h), que revelou IC50 de 250,22 µM para a SLB. A atividade tripanocida avaliada por método com resazurina em epimastigotas (24h) mostrou que a SLB 25 µM inibiu o crescimento dos parasitos. O ensaio em amastigotas revelou índice de seletividade de 3,13, além de mostrar a maior porcentagem de inibição (> 90%) quando a SLB foi usada na associação de SLB100+BZ10µM, em comparação com SLB (100; 25; 6,25 µM) ou BZ (10; 5; 2,5 µM) isolados. No ensaio in vivo, camundongos Swiss comprovadamente infectados IP com 10.000 tripomastigotas sanguíneos foram tratados por via oral por 20 dias consecutivos com SLB50, SLB150, SLB50+BZ25, SLB50+BZ50, SLB50+BZ100, SLB150+BZ25, SLB150+BZ50, SLB150+BZ100, BZ25, BZ50 e BZ100 mg/kg/dia. Os animais foram avaliados diariamente na fase aguda (parasitemia) e aos 90, 180 e 240 dias após tratamento por hemocultura, qPCR de eluato sanguíneo e sorologia (ELISA). Após a eutanásia, foram feitas, além das avaliações anteriores, a qPCR do tecido cardíaco. Os resultados in vivo demonstraram que a SLB em monoterapia não foi capaz de controlar a parasitemia e a mortalidade dos animais. As avaliações parasitológicas mostraram 100% de negatividade na maioria dos grupos de animais tratados com combinação de drogas ou doses menores de BZ, enquanto a sorologia foi positiva em todos os animais não sendo constatada cura pelo critério clássico. Entretanto verificamos que os grupos experimentais tratados com BZ em menores doses e que os tratados com BZ em menores doses quando associado a SLB apresentaram maior negatividade nos exames parasitológicos, porém sem diferenças significativas entre os demais grupos. Análise histopatológica cardíaca será feita para avaliar se houve redução da inflamação/fibrose entre os grupos tratados com a associação SLB+BZ versus BZ.
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    Benznidazole, itraconazole and their combination in the treatment of acute experimental chagas disease in dogs.
    (2019) Cunha, Eleonora Lima Alves; Torchelsen, Fernanda Karoline Vieira da Silva; Cunha, Lucas Maciel; Oliveira, Maykon Tavares de; Fonseca, Kátia da Silva; Vieira, Paula Melo de Abreu; Carneiro, Cláudia Martins; Lana, Marta de
    Chagas disease (CD) is a serious public health problem in Latin America and its treatment remains neglected. Benznidazole (BZ), the only drug available in Brazil, presents serious side effects and low therapeutic efficacy, especially at the chronic phase. The last clinical trials demonstrated that the first generation of azole compounds were less successful than BZ in CD chemotherapy, which stimulated studies of these compounds associated to BZ and nifurtimox (NF). This study evaluated the therapeutic efficacy of BZ, itraconazole (ITZ) and their combination (BZ + ITZ) in dogs infected with the VL-10 T. cruzi strain in the acute phase of the disease. Twenty young mongrel dogs were inoculated with 2.0 × 103 blood trypomastigotes/kg and divided into four groups: treated with BZ, ITZ and BZ + ITZ for 60 days, and control group (INT). The parasitemia of the BZ + ITZ and BZ groups were similar and showed significant reduction compared to the INT group. The group treated with ITZ also showed significant parasitemia reduction compared to the INT group. The global analysis of hemoculture (HC), blood PCR, conventional serology (CS-ELISA), heart qPCR and histopathology techniques, used in the post-treatment evaluation, revealed that BZ + ITZ combination lead to a more reduction of parasitemia during the acute phase and heart qPCR positivity, less cardiac damage (inflammation and fibrosis in the left ventricle) and total survival. According to the classical cure criteria one animal treated with BZ + ITZ can be considered cured in its final evaluation and two other dogs, one of this group and one treated with ITZ were in process of cure. At least for BZ-resistant T. cruzi strains such as VL-10, BZ + ITZ was not effective to induce parasitological cure or a profound and sustained reduction of the parasite burden in blood and infected organs.
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    Benznidazole, itraconazole, and their combination for the treatment of chronic experimental Chagas disease in dogs.
    (2022) Cunha, Eleonora Lima Alves; Torchelsen, Fernanda Karoline Vieira da Silva; Fonseca, Kátia da Silva; Sousa, Lucas Resende Dutra; Vieira, Paula Melo de Abreu; Carneiro, Cláudia Martins; Pinto, Kelerson Mauro de Castro; Torres, Rosália Morais; Lana, Marta de
    Treatment for Chagas disease has limited efficacy in the chronic phase. We evaluated benznidazole (BZ) and itraconazole (ITZ) individually and in association in dogs 16 months after infection with a BZ-resistant Trypa- nosoma cruzi strain. Four study groups (20 animals) were evaluated and treated for 60 days with BZ, ITZ, or BZ + ITZ, and maintained in parallel to control group infected and not treated (INT). All dogs were evaluated in the first, sixth, 12th, 18th and 24th months of study. Polymerase chain reaction (PCR) was negative in 2 of 3 animals in the BZ + ITZ group, 2 of 5 in the BZ group, and 4 of 5 in the ITZ group. Hemoculture performed in the 24th month was negative in all groups. Enzyme-linked immunoassay remained reactive in all treated animals. Echocardiography differentiated treated animals from control animals. Quantitative PCR analysis of cardiac tissue was negative in the BZ + ITZ and BZ groups, positive in 2 of 5 dogs in the ITZ group and in 2 of 3 dogs in the control group, but negative in colon tissue in all groups. Inflammation was significantly reduced in the right atrium and left ventricle of dogs treated with BZ + ITZ and BZ compared with those receiving ITZ alone. Fibrosis was absent in most dogs treated with BZ + ITZ, mild in those treated with BZ or ITZ alone, and intense in the control group. Parasitological and histopathological evaluations showed that BZ + ITZ treatment improved or stabilized the clinical condition of the dogs.
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    Evaluation of the anti-Trypanosoma cruzi activity in vitro and in vivo of silibinin and silibinin in association to benznidazole.
    (2020) Torchelsen, Fernanda Karoline Vieira da Silva; Silva, Thaila Martins; Milagre, Matheus Marques; Silva, Rafael Rodrigues; Reis, Levi Eduardo Soares; Branquinho, Renata Tupinambá; Silva, Glenda Nicioli da; Lana, Marta de
    Chagas disease (CD) is endemic in Latin America. Drugs available for its treatment are benznidazole (BZ)/nifurtimox (NF), both with low efficacy in the late infection and responsible for several side effects. Studies of new drugs for CD among natural products, and using drug combinations with BZ/NF are recommended. Silibinin (SLB) is a natural compound that inhibits the efflux pump (Pgp) of drugs in host cell membranes, causes death of trypanosomatids, has anti-inflammatory activity, and was never assayed against T. cruzi. Here, in vitro and in vivo activities of SLB, SLB+BZ, and BZ against T. cruzi Y strain were evaluated. Cytotoxicity of SLB in VERO cells by the MTT method revealed IC50 of 250.22 μM. The trypanocidal activity evaluated by resazurin method in epimastigotes showed that SLB 25 μM inhibited parasite growth. SLB IC50 and selectivity index (SI) for amastigote were 79.81 μM and 3.13, respectively. SLB100+BZ10 showed higher parasite inhibition (91.44%) than SLB or BZ. Swiss mice infected with Y strain were treated with SLB, SLB+BZ, and BZ. Parasitemia was evaluated daily and 90, 180, and 240 days after treatment in surviving animals by hemoculture, blood qPCR, and after euthanasia, by qPCR in heart tissue. SLB monotherapy was not able to control the parasitemia/mortality of the animals. Parasitological negativation of 85.7– 100% was observed in the experimental groups treated with SLB+BZ. Although SLB had shown activity against T. cruzi in vitro, it was not active in mice. Thus, the results of the therapeutic effect observed with SLB+BZ may be interpreted as a result from BZ action.