Browsing by Author "Braga, Saulo Fehelberg Pinto"

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    Antidepressant-like effect of terpineol in an inflammatory model of depression : involvement of the cannabinoid system and d2 dopamine receptor.
    (2020) Vieira, Graziela; Cavalli, Juliana; Gonçalves, Elaine Cristina Dalazen; Braga, Saulo Fehelberg Pinto; Ferreira, Rafaela Salgado; Santos, Adair Roberto Soares; Cola, Maíra; Raposo, Nádia Rezende Barbosa; Capasso, Raffaele; Dutra, Rafael Cypriano
    Depression has a multifactorial etiology that arises from environmental, psychological, genetic, and biological factors. Environmental stress and genetic factors acting through immunological and endocrine responses generate structural and functional changes in the brain, inducing neurogenesis and neurotransmission dysfunction. Terpineol, monoterpenoid alcohol, has shown immunomodulatory and neuroprotective effects, but there is no report about its antidepressant potential. Herein, we used a single lipopolysaccharide (LPS) injection to induce a depressive-like effect in the tail suspension test (TST) and the splash test (ST) for a preventive and therapeutic experimental schedule. Furthermore, we investigated the antidepressant-likemechanism of action of terpineol while usingmolecular and pharmacological approaches. Terpineol showed a coherent predicted binding mode mainly against CB1 and CB2 receptors and also against the D2 receptor during docking modeling analyses. The acute administration of terpineol produced the antidepressant-like effect, since it significantly reduced the immobility time in TST (100–200 mg/kg, p.o.) as compared to the control group. Moreover, terpineol showed an antidepressant-like effect in the preventive treatment that was blocked by a nonselective dopaminergic receptor antagonist (haloperidol), a selective dopamine D2 receptor antagonist (sulpiride), a selective CB1 cannabinoid receptor antagonist/inverse agonist (AM281), and a potent and selective CB2 cannabinoid receptor inverse agonist (AM630), but it was not blocked by a nonselective adenosine receptor antagonist (caffeine) or a β-adrenoceptor antagonist (propranolol). In summary, molecular docking suggests that CB1 and CB2 receptors are the most promising targets of terpineol action. Our data showed terpineol antidepressant-like modulation by CB1 and CB2 cannabinoid receptors and D2-dopaminergic receptors to further corroborate our molecular evidence.
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    Brazilian essential oils as source for the discovery of new anti-COVID-19 drug : a review guided by in silico study.
    (2021) Amparo, Tatiane Roquete; Seibert, Janaína Brandão; Silveira, Benila Maria; Costa, Fernanda Senna Ferreira; Almeida, Tamires Cunha; Braga, Saulo Fehelberg Pinto; Silva, Glenda Nicioli da; Santos, Orlando David Henrique dos; Souza, Gustavo Henrique Bianco de
    The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China and its spread worldwide has become one of the biggest health problem due to the lack of knowledge about an effective chemotherapy. Based on the current reality of the SARS-CoV-2 pandemic, this study aimed to make a review literature about potential anti-coronavirus natural compounds guided by an in silico study. In the first step, essential oils from native species found in the Brazilian herbal medicine market and Brazilian species that have already shown antiviral potential were used as source for the literature search and compounds selection. Among these compounds, 184 showed high antiviral potential against rhinovirus or picornavirus by quantitative structure–activity relationship analysis. (E)-a-atlantone; 14-hydroxy-amuurolene; allo-aromadendrene epoxide; amorpha4,9-dien-2-ol; aristochene; azulenol; germacrene A; guaia-6,9-diene; hedycaryol; humulene epoxide II; aamorphene; a-cadinene; a-calacorene and a-muurolene showed by a molecular docking study the best result for four target proteins that are essential for SARS-CoV-2 lifecycle. In addition, other parameters obtained for the selected compounds indicated low toxicity and showed good probability to achieve cell permeability and be used as a drug. These results guided the second literature search which included other species in addition to native Brazilian plants. The majority presence of any of these compounds was reported for essential oils from 45 species. In view of the few studies relating essential oils and antiviral activity, this review is important for future assays against the new coronavirus.
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    Discovery and characterization of trypanocidal cysteine protease inhibitors from the ‘malaria box’.
    (2019) Pereira, Glaécia Aparecida do Nascimento; Silva, Elany Barbosa da; Braga, Saulo Fehelberg Pinto; Leite, Paulo Gaio; Martins, Luan Carvalho; Vieira, Rafael Pinto; Soh, Wai Tuck; Villela, Filipe Silva; Costa, Francielly Morais Rodrigues da; Ray, Debalina; Andrade, Saulo Fernandes de; Brandstetter, Hans; Oliveira, Renata Barbosa; Caffrey, Conor R.; Machado, Fabiana Simão; Ferreira, Rafaela Salgado
    Chagas disease, Human African Trypanosomiasis, and schistosomiasis are neglected parasitic diseases for which new treatments are urgently needed. To identify new chemical leads, we screened the 400 compounds of the Open Access Malaria Box against the cysteine proteases, cruzain (Trypanosoma cruzi), rhodesain (Trypanosoma brucei) and SmCB1 (Schistosoma mansoni), which are therapeutic targets for these diseases. Whereas just three hits were observed for SmCB1, 70 compounds inhibited cruzain or rhodesain by at least 50% at 5 mM. Among those, 15 commercially available compounds were selected for confirmatory assays, given their potency, time-dependent inhibition profile and reported activity against parasites. Additional assays led to the confirmation of four novel classes of cruzain and rhodesain in- hibitors, with potency in the low-to mid-micromolar range against enzymes and T. cruzi. Assays against mammalian cathepsins S and B revealed inhibitor selectivity for parasitic proteases. For the two competitive inhibitors identified (compounds 7 and 12), their binding mode was predicted by docking, providing a basis for structure-based optimization efforts. Compound 12 also acted directly against the trypomastigote and the intracellular amastigote forms of T. cruzi at 3 mM. Therefore, through a combi- nation of experimental and computational approaches, we report promising hits for optimization in the development of new trypanocidal drugs.
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    Glucosyl-1,2,3-triazoles derived from eugenol and analogues : synthesis, anti-Candida activity, and molecular modeling studies in CYP-51.
    (2021) Magalhães, Lorena Severiano de; Reis, Adriana Cotta Cardoso; Nakao, Izadora Amaral; Péret, Vinícius Augusto Campos; Reis, Rúbia Castro Fernandes Melo; Silva, Naiara Chaves; Dias, Amanda Latércia Tranches; Carvalho, Diogo Teixeira; Dias, Danielle Ferreira; Brandão, Geraldo Célio; Braga, Saulo Fehelberg Pinto; Souza, Thiago Belarmino de
    This work describes the synthesis, anti-Candida, and molecular modeling stud- ies of eighteen new glucosyl-1,2,3-triazoles derived from eugenol and corre- lated phenols. The new compounds were characterized by combined Fourier Transform Infrared, 1 H and 13C nuclear magnetic resonance and spectroscopy of high-resolution mass spectrometry. The synthesized compounds did not show significant cytotoxicity against healthy fibroblast human cells (MCR-5) providing interesting selectivity indexes (SI) to active compounds. Considering the antifun- gal activity, nine compounds showed anti-Candida potential and the peracety- lated triazoles 17 and 18 were the most promising ones. Eugenol derivative 17 was active against three species of Candida at 26.1–52.1 μM. This compound was four times more potent than fluconazole against Candida krusei and less toxic (SI > 6.6) against the MCR-5 cells than fluconazole (SI > 3.3) considering this strain. Dihydroeugenol derivative 18 showed similar activity to 17 and was four times more potent and less toxic than fluconazole against C. krusei. The deacety- lated glucosides and non-glucosylated corresponding derivatives did not show considerable antifungal action, suggesting that the acetyl groups are essential for their anti-Candida activity. Molecular docking coupled with molecular dynam- ics showed that 14α-lanosterol demethylase is a feasible molecular target, since 17 and 18 could bind to this enzyme once deacetylated in vivo, thereby acting as prodrugs. Also, these studies demonstrated the importance of hydrophobic sub- stituents at the phenyl ring.
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    Purity determination of a new antifungal drug candidate using quantitative 1H NMR spectroscopy : method validation and comparison of calibration approaches.
    (2019) Franco, Pedro Henrique Cavalcanti; Braga, Saulo Fehelberg Pinto; Oliveira, Renata Barbosa de; César, Isabela Costa
    Quantitative nuclear magnetic resonance (qNMR) is an analytical technique that offers numerous advantages in pharmaceutical applications including minimum sample preparation and rapid data collection times with no need for response factor corrections, being a powerful tool for assaying drug content in both drug discovery and early drug development. In the present work, we have applied qNMR, using both the internal standard and the electronic refer- ence to access in vivo concentrations 2 calibration methods, to assess the purity of RI76, a novel antifungal drug candidate. NMR acquisition and processing parameters were optimized in order to obtain spectra with intense, well‐ resolved signals of completely relaxed nuclei. The analytical method was vali- dated following current guidelines, demonstrating selectivity, linearity, accu- racy, precision, and robustness. The calibration approaches were statistically compared, and no significant difference was observed when comparing the obtained results and their dispersion in terms of relative standard deviation. The proposed qNMR method may, therefore, be used for both qualitative and quantitative assessments of RI76 in early drug development and for character- ization of this compound.
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    Synthesis and structural characterization of new benzylidene glycosides, cytotoxicity against cancer cell lines and molecular modeling studies.
    (2021) Péret, Vinícius Augusto Campos; Reis, Adriana Cotta Cardoso; Silva, Naiara Chaves; Dias, Amanda Latercia Tranches; Carvalho, Diogo Teixeira; Dias, Danielle Ferreira; Braga, Saulo Fehelberg Pinto; Brandão, Geraldo Célio; Souza, Thiago Belarmino de
    This work describes the synthesis, structural characterization (by combined Fourier Transform Infrared - FTIR, 1H and 13C Nuclear Magnetic Resonance - NMR spectroscopy and High Resolution Mass Spectrometry - HRMS) and biological evaluation of a new series of glycosides designed from a benzylidene glucoside derived from eugenol (23) active against Candida glabrata. The mass accuracy between the calculated and found values observed in HRMS analyses were lower than 5 ppm, which are acceptable for proposing a molecular formula using this technique. We decided to keep the benzylidene group of 23, while changing either the saccharide unit (glucose or galactose) or the natural aglycone (eugenol, isoeugenol, dihydroeugenol or guaiacol) to check their influence in antifungal activity. Since the chemical modifications performed did not contribute to enhance the antifungal activity, the synthesized compounds (23– 30) were further screened against four cancer cell lines (HeLa: cervix carcinoma; MDA-MB-231: breast carcinoma; T-24: urinary bladder carcinoma; and TOV-21G: ovarian carcinoma). The glucoside 27 showed promising activities (IC50 10.08–59.91 μM) against all the assayed cancer cell lines and higher values of selectivity index than doxorubicin, the control drug. The galactoside 28 demonstrated interesting results against HeLa, MDA-MB-231 and T-24 cells. This compound was active at 17.41 μM with a selectivity index greater than 13.7 against the HeLa cells, while doxorubicin was active at 10.01 μM with a selectivity index close to 1.5 considering this cell line. Further, we performed docking studies of these compounds with type II topoisomerase-DNA complex (TOP2) in order to try to explain their mechanism of action.