Publications by authors named "Patricia B da Silva"

13 Publications

  • Page 1 of 1

Characterization and trypanocidal activity of a β-lapachone-containing drug carrier.

PLoS One 2021 4;16(3):e0246811. Epub 2021 Mar 4.

Laboratório de Biologia Celular Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.

The treatment of Chagas disease (CD), a neglected parasitic condition caused by Trypanosoma cruzi, is still based on only two drugs, nifurtimox (Nif) and benznidazole (Bz), both of which have limited efficacy in the late chronic phase and induce severe side effects. This scenario justifies the continuous search for alternative drugs, and in this context, the natural naphthoquinone β-lapachone (β-Lap) and its derivatives have demonstrated important trypanocidal activities. Unfortunately, the decrease in trypanocidal activity in the blood, high toxicity to mammalian cells and low water solubility of β-Lap limit its systemic administration and, consequently, clinical applications. For this reason, carriers as drug delivery systems can strategically maximize the therapeutic effects of this drug, overcoming the above mentioned restrictions. Accordingly, the aim of this study is to investigate the in vitro anti-T. cruzi effects of β-Lap encapsulated in2-hydroxypropyl-β-cyclodextrin (2HP-β-CD) and its potential toxicity to mammalian cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246811PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7932091PMC
March 2021

A Novel Antifungal System With Potential for Prolonged Delivery of Histatin 5 to Limit Growth of .

Front Microbiol 2019 30;10:1667. Epub 2019 Jul 30.

Department of Biochemistry and Chemical Technology, Institute of Chemistry, UNESP - São Paulo State University, Araraquara, Brazil.

Currently 75-88% of fungal infections are caused by species, and is the main microorganism that causes these infections, especially oral candidiasis. An option for treatment involves the use of the antifungal peptide Histatin 5 (Hst 5), which is naturally found in human saliva but undergoes rapid degradation when present in the oral cavity, its site of action. For this reason, it is important to develop a way of applying this peptide to the oral lesions, which promotes the gradual release of the peptide. In the present study, we have evaluated the development of liposomes of different lipid compositions, loaded with the peptide as a way to promote its release slowly and gradually, preserving its antifungal potential. For this, the peptide 0WHistatin 5, an analog of the peptide Hst 5, was synthesized, which contains the amino acid tryptophan in its sequence. The solid phase synthesis method was used, followed by cleavage and purification. The liposomes were produced by thin film hydration technique in three different lipid compositions, F1, F2, and F3 and were submitted to an extrusion and sonication process to standardize the size and study the best technique for their production. The liposomes were characterized by dynamic light scattering, and tests were performed to determine the encapsulation efficiency, release kinetics, stability, and evaluation of antifungal activity. The extruded liposomes presented average size in the range of 100 nm, while sonicated liposomes presented a smaller size in the range of 80 nm. The encapsulation efficiency was higher for the sonicated liposomes, being 34.5% for F1. The sonicated F3 presented better stability when stored for 60 days at 4°C. The liposomes showed the ability to release the peptide for the total time of 96 h, with the first peak after 5 h, and a further increase of the released after 30 h. Time-kill assay showed that the liposomes were able to control yeast growth for 72 h. The data suggest that the liposomes loaded with 0WHistatin 5 maintained the action of the peptide and were able to limit the growth of , being a suitable system for use in the treatment of oral candidiasis.
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http://dx.doi.org/10.3389/fmicb.2019.01667DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683761PMC
July 2019

A Nanostructured Lipid System to Improve the Oral Bioavailability of Ruthenium(II) Complexes for the Treatment of Infections Caused by .

Front Microbiol 2018 6;9:2930. Epub 2018 Dec 6.

School of Pharmaceutical Sciences, Universidade Estadual Paulista, Araraquara, Brazil.

Tuberculosis (TB) is an infectious, airborne disease caused by the bacterium that mainly affects the lungs. Fortunately, tuberculosis is a curable disease, and in recent years, death rates for this disease have decreased. However, the existence of antibiotic-resistant strains and the occurrence of co-infections with human immunodeficiency virus (HIV), have led to increased mortality in recent years. Another area of concern is that one-third of the world's population is currently infected with in its latent state, serving as a potential reservoir for active TB. In an effort to address the failure of current TB drugs, greater attention is being given to the importance of bioinorganic chemistry as an ally in new research into the development of anti-TB drugs. Ruthenium (Ru) is a chemical element that can mimic iron (Fe) in the body. In previous studies involving the following heteroleptic Ru complexes, [Ru(pic)(dppb)(bipy)]PF (SCAR1), [Ru(pic)(dppb)(Me-bipy)]PF (SCAR2), [Ru(pic)(dppb)(phen)]PF (SCAR4), -[Ru(pic)(dppe)]PF (SCAR5), and [Ru(pic)(dppe)(phen)]PF (SCAR7), we observed excellent anti-TB activity, moderate cell-toxicity, and a lack of oral bioavailability in an model of these complexes. Therefore, the objective of this study was to evaluate the toxicity and oral bioavailability of these complexes by loading them into a nanostructured lipid system. The nanostructured lipid system was generated using different ratios of surfactant (soybean phosphatidylcholine, Eumulgin, and sodium oleate), aqueous phase (phosphate buffer with a concentration of 1X and pH 7.4), and oil (cholesterol) to generate a system for the incorporation of Ru(II) compounds. The anti-TB activity of the compounds was determined using a microdilution assay with Resazurin (REMA) against strains of s HRv and clinical isolates resistant. Cytotoxicity assay using J774.A1 cells (ATCC TIB-67) and intra-macrophage activity were performed. The oral bioavailability assay was used to analyze blood collected from female BALB/C mice. Plasma collected from the same mice was analyzed via inductively coupled plasma mass spectrometry (ICP-MS) to quantify the number of Ru ions. The complexes loaded into the nanostructured lipid system maintained activity and toxicity was found to be reduced compared with the compounds that were not loaded. The complexes showed intra-macrophagic activity and were orally bioavailable.
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http://dx.doi.org/10.3389/fmicb.2018.02930DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6291527PMC
December 2018

Determination of in vitro absorption in Caco-2 monolayers of anticancer Ru(II)-based complexes acting as dual human topoisomerase and PARP inhibitors.

Biometals 2019 02 30;32(1):89-100. Epub 2018 Nov 30.

Center of Exact Sciences and Technology, Federal University of São Carlos, São Carlos, SP, 13565-905, Brazil.

Due to their unique and versatile biochemical properties, ruthenium-based compounds have emerged as promising anticancer agents. Previous studies showed that three ruthenium(II) compounds: [Ru(pySH)(bipy)(dppb)]PF (1), [Ru(HSpym)(bipy)(dppb)]PF (2) and Ru[(SpymMe)(bipy)(dppb)]PF (3) presented anticancer properties higher than doxorubicin and cisplatin and acted as human topoisomerase IB (Topo I) inhibitors. Here, we focused our studies on in vitro intestinal permeability and anticancer mechanisms of these three complexes. Caco-2 permeation studies showed that 1 did not permeate the monolayer of intestinal cells, suggesting a lack of absorption on oral administration, while 2 and 3 permeated the cells after 60 and 120 min, respectively. Complexes 2 and 3 fully inhibited Topo II relaxation activity at 125 µM. In previously studies, 3 was the most potent inhibitor of Topo I, here, we concluded that it is a dual topoisomerase inhibitor. Moreover, it presented selectivity to cancer cells when evaluated by clonogenic assay. Thus, 3 was selected to gene expression assay front MDA-MB-231 cells from triple-negative breast cancer (TNBC), which represents the highly aggressive subgroup of breast cancers with poor prognosis. The analyses revealed changes of 27 out of 84 sought target genes. PARP1 and PARP2 were 5.29 and 1.83 times down-regulated after treatment with 3, respectively. PARPs have been attractive antitumor drug targets, considering PARP inhibition could suppress DNA damage repair and sensitize tumor cells to DNA damage agents. Recent advances in DNA repair studies have shown that an approach that causes cell lethality using synthetic PARP-inhibiting drugs has produced promising results in TNBC.
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http://dx.doi.org/10.1007/s10534-018-0160-0DOI Listing
February 2019

, , and Analyses of Novel Aromatic Amidines against Trypanosoma cruzi.

Antimicrob Agents Chemother 2018 02 25;62(2). Epub 2018 Jan 25.

Laboratory of Cellular Biology (LBC), Oswaldo Cruz Institute (Fiocruz), Rio de Janeiro, RJ, Brazil

Five bis-arylimidamides were assayed as anti- agents by , , and approaches. None were considered to be pan-assay interference compounds. They had a favorable pharmacokinetic landscape and were active against trypomastigotes and intracellular forms, and in combination with benznidazole, they gave no interaction. The most selective agent (28SMB032) tested led to a 40% reduction in parasitemia (0.1 mg/kg of body weight/5 days intraperitoneally) but without mortality protection. target fishing suggested DNA as the main target, but ultrastructural data did not match.
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http://dx.doi.org/10.1128/AAC.02205-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786784PMC
February 2018

Nanostructured lipid carriers for incorporation of copper(II) complexes to be used against .

Drug Des Devel Ther 2017 20;11:909-921. Epub 2017 Mar 20.

Department of Drugs and Medicines, Faculdade de Ciências Farmacêuticas, UNESP - Univ Estadual Paulista, Campus Araraquara, Araraquara, SP, Brazil.

Tuberculosis (TB) is a disease caused by . Cessation of treatment before the recommended conclusion may lead to the emergence of multidrug-resistant strains. The aim of this study was to develop nanostructured lipid carriers (NLCs) for use in the treatment of . The NLCs comprised the following lipid phase: 2.07% polyoxyethylene 40 stearate, 2.05% caprylic/capric triglyceride, and 0.88% polyoxyl 40 hydrogenated castor oil; the following aqueous phase: 3.50% poloxamer 407 (F1-F6), and 0.50% cetyltrimethylammonium bromide (F7-F12); and incorporated the copper(II) complexes [CuCl(INH)]·HO (1), [Cu(NCS)(INH)]·5HO (2), and [Cu(NCO)(INH)]·4HO (3) to form compounds F11.1, F11.2, and F11.3, respectively. The mean diameter of F11, F11.1, F11.2, and F11.3 ranged from 111.27±21.86 to 134.25±22.72 nm, 90.27±12.97 to 116.46±9.17 nm, 112.4±10.22 to 149.3±15.82 nm, and 78.65±6.00 to 122.00±8.70 nm, respectively. The polydispersity index values for the NLCs ranged from 0.13±0.01 to 0.30±0.09. The NLCs showed significant changes in zeta potential, except for F11.2, with F11, F11.1, F11.2, and F11.3 ranging from 18.87±4.04 to 23.25±1.13 mV, 17.03±1.77 to 21.42±1.87 mV, 20.51±1.88 to 22.60±3.44 mV, and 17.80±1.96 to 25.25±7.78 mV, respectively. Atomic force microscopy confirmed the formation of nanoscale spherical particle dispersions by the NLCs. Differential scanning calorimetry determined the melting points of the constituents of the NLCs. The in vitro activity of copper(II) complex-loaded NLCs against HR showed an improvement in the anti-TB activity of 55.4, 27.1, and 41.1 times the activity for complexes 1, 2, and 3, respectively. An in vivo acute toxicity study of complex-loaded NLCs demonstrated their reduced toxicity. The results suggest that NLCs may be a powerful tool to optimize the activity of copper(II) complexes against .
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http://dx.doi.org/10.2147/DDDT.S127048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5367736PMC
May 2017

Novel Zinc(II) Complexes [Zn(atc-Et)₂] and [Zn(atc-Ph)₂]: In Vitro and in Vivo Antiproliferative Studies.

Int J Mol Sci 2016 May 21;17(5). Epub 2016 May 21.

Faculdade de Ciencias Farmaceuticas, UNESP-Univ Estadual Paulista, Campus Araraquara, Araraquara, São Paulo 14800-903, Brazil.

Cisplatin and its derivatives are the main metallodrugs used in cancer therapy. However, low selectivity, toxicity and drug resistance are associated with their use. The zinc(II) (Zn(II)) thiosemicarbazone complexes [Zn(atc-Et)₂] (1) and [Zn(atc-Ph)₂] (2) (atc-R: monovalent anion of 2-acetylpyridine N4-R-thiosemicarbazone) were synthesized and fully characterized in the solid state and in solution via elemental analysis, Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) and proton nuclear magnetic resonance (¹H NMR) spectroscopy, conductometry and single-crystal X-ray diffraction. The cytotoxicity of these complexes was evaluated in the HepG2, HeLa, MDA-MB-231, K-562, DU 145 and MRC-5 cancer cell lines. The strongest antiproliferative results were observed in MDA-MB-231 and HepG2 cells, in which these complexes displayed significant selective toxicity (3.1 and 3.6, respectively) compared with their effects on normal MRC-5 cells. In vivo studies were performed using an alternative model (Artemia salina L.) to assure the safety of these complexes, and the results were confirmed using a conventional model (BALB/c mice). Finally, tests of oral bioavailability showed maximum plasma concentrations of 3029.50 µg/L and 1191.95 µg/L for complexes 1 and 2, respectively. According to all obtained results, both compounds could be considered as prospective antiproliferative agents that warrant further research.
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http://dx.doi.org/10.3390/ijms17050781DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4881598PMC
May 2016

In Vitro Activity of Copper(II) Complexes, Loaded or Unloaded into a Nanostructured Lipid System, against Mycobacterium tuberculosis.

Int J Mol Sci 2016 May 17;17(5). Epub 2016 May 17.

Faculdade de Ciencias Farmaceuticas, UNESP-Univ Estadual Paulista, Campus Araraquara, Araraquara, São Paulo 14800-903, Brazil.

Tuberculosis (TB) is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb), presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS) composed of 10% phase oil (cholesterol), 10% surfactant (soy phosphatidylcholine, sodium oleate), and Eumulgin(®) HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8), and an 80% aqueous phase (phosphate buffer pH = 7.4) as a tactic to enhance the in vitro anti-Mtb activity of the copper(II) complexes [CuCl₂(INH)₂]·H₂O (1), [Cu(NCS)₂(INH)₂]·5H₂O (2) and [Cu(NCO)₂(INH)₂]·4H₂O (3). The Cu(II) complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI) varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from -0.00690 ± 0.0896 to -8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H37Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI) was calculated using the cytotoxicity index (IC50) against Vero (ATCC(®) CCL-81), J774A.1 (ATCC(®) TIB-67), and MRC-5 (ATCC(®) CCL-171) cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.). These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB.
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http://dx.doi.org/10.3390/ijms17050745DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4881567PMC
May 2016

A Nanostructured Lipid System as a Strategy to Improve the in Vitro Antibacterial Activity of Copper(II) Complexes.

Molecules 2015 Dec 16;20(12):22534-45. Epub 2015 Dec 16.

School of Pharmaceutical Sciences, UNESP-University Estadual Paulista, Campus Araraquara, Araraquara, 14801-902 São Paulo, Brazil.

The aim of this study was to construct a nanostructured lipid system as a strategy to improve the in vitro antibacterial activity of copper(II) complexes. New compounds with the general formulae [CuX₂(INH)₂]·nH₂O (X = Cl(-) and n = 1 (1); X = NCS(-) and n = 5 (2); X = NCO(-) and n = 4 (3); INH = isoniazid, a drug widely used to treat tuberculosis) derived from the reaction between the copper(II) chloride and isoniazid in the presence or absence of pseudohalide ions (NCS(-) or NCO(-)) were synthesized and characterized by infrared spectrometry, electronic absorption spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, elemental analysis, melting points and complexometry with 2,2',2'',2'''-(Ethane-1,2-diyldinitrilo)tetraacetic acid (EDTA). The characterization techniques allowed us to confirm the formation of the copper(II) complexes. The Cu(II) complexes were loaded into microemulsion (MEs) composed of 10% phase oil (cholesterol), 10% surfactant [soy oleate and Brij(®) 58 (1:2)] and 80% aqueous phase (phosphate buffer pH = 7.4) prepared by sonication. The Cu(II) complex-loaded MEs displayed sizes ranging from 158.0 ± 1.060 to 212.6 ± 1.539 nm, whereas the polydispersity index (PDI) ranged from 0.218 ± 0.007 to 0.284 ± 0.034. The antibacterial activity of the free compounds and those that were loaded into the MEs against Staphylococcus aureus ATCC(®) 25923 and Escherichia coli ATCC(®) 25922, as evaluated by a microdilution technique, and the cytotoxicity index (IC50) against the Vero cell line (ATCC(®) CCL-81(TM)) were used to calculate the selectivity index (SI). Among the free compounds, only compound 2 (MIC 500 μg/mL) showed activity for S. aureus. After loading the compounds into the MEs, the antibacterial activity of compounds 1, 2 and 3 was significantly increased against E. coli (MIC's 125, 125 and 500 μg/mL, respectively) and S. aureus (MICs 250, 500 and 125 μg/mL, respectively). The loaded compounds were less toxic against the Vero cell line, especially compound 1 (IC50 from 109.5 to 319.3 μg/mL). The compound 2- and 3-loaded MEs displayed the best SI for E. coli and S. aureus, respectively. These results indicated that the Cu(II) complex-loaded MEs were considerably more selective than the free compounds, in some cases, up to 40 times higher.
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http://dx.doi.org/10.3390/molecules201219822DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6332266PMC
December 2015

Reading component skills in dyslexia: word recognition, comprehension and processing speed.

Front Psychol 2014 28;5:1339. Epub 2014 Nov 28.

Developmental Disorders Program, Center for Health and Biological Science, Mackenzie Presbyterian University Sao Paulo, Brazil.

The cognitive model of reading comprehension (RC) posits that RC is a result of the interaction between decoding and linguistic comprehension. Recently, the notion of decoding skill was expanded to include word recognition. In addition, some studies suggest that other skills could be integrated into this model, like processing speed, and have consistently indicated that this skill influences and is an important predictor of the main components of the model, such as vocabulary for comprehension and phonological awareness of word recognition. The following study evaluated the components of the RC model and predictive skills in children and adolescents with dyslexia. 40 children and adolescents (8-13 years) were divided in a Dyslexic Group (DG; 18 children, MA = 10.78, SD = 1.66) and control group (CG 22 children, MA = 10.59, SD = 1.86). All were students from the 2nd to 8th grade of elementary school and groups were equivalent in school grade, age, gender, and IQ. Oral and RC, word recognition, processing speed, picture naming, receptive vocabulary, and phonological awareness were assessed. There were no group differences regarding the accuracy in oral and RC, phonological awareness, naming, and vocabulary scores. DG performed worse than the CG in word recognition (general score and orthographic confusion items) and were slower in naming. Results corroborated the literature regarding word recognition and processing speed deficits in dyslexia. However, dyslexics can achieve normal scores on RC test. Data supports the importance of delimitation of different reading strategies embedded in the word recognition component. The role of processing speed in reading problems remain unclear.
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http://dx.doi.org/10.3389/fpsyg.2014.01339DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4246655PMC
December 2014

In vitro analyses of the effect of aromatic diamidines upon Trypanosoma cruzi.

J Antimicrob Chemother 2009 Oct 11;64(4):747-50. Epub 2009 Aug 11.

Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil.

Objectives: Aromatic diamidines (ADs) have been recognized as promising antiparasitic agents. Therefore, in the present work, the in vitro trypanocidal effect of 11 ADs upon the relevant clinical forms of Trypanosoma cruzi was evaluated, as well as determining their toxicity to mammalian cells and their subcellular localization.

Methods: The trypanocidal effect upon trypomastigotes and amastigotes was evaluated by light microscopy through the determination of the IC(50) values. The cytotoxicity was determined by the MTT colorimetric assay against mouse cardiomyocytes. For the subcellular localization, transmission electron microscopy and fluorescence approaches were used. The fluorescence intensity within the kinetoplast DNA (kDNA) and nuclear DNA (nDNA) of treated parasites was determined using the Image J program.

Results: Compounds 2, 5 and 7 showed the lowest IC(50) values (micromolar range) against intracellular amastigotes and trypomastigotes. In the presence of blood, all the tested ADs exhibited a reduction of their activity. The compounds did not exhibit toxicity to cardiac cells and the highest selectivity index (SI) was achieved by compound 5 with an SI of >137 for trypomastigotes and compound 7 with an SI of >107 for intracellular parasites. The subcellular effects upon bloodstream forms treated with compounds 5 and 7 were mainly on kDNA, leading to its disorganization. The higher accumulation in the kDNA observed for all tested ADs was not directly related to their efficacy.

Conclusions: Our results show the high activity of this new series of ADs against both trypomastigote and amastigote forms, with excellent SIs, especially compound 7, which merits further in vivo evaluation.
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http://dx.doi.org/10.1093/jac/dkp290DOI Listing
October 2009
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