Further Investigations of Nitroheterocyclic Compounds as Potential Antikinetoplastid Drug Candidates.

Due to the lack of specific vaccines, management of the trypanosomatid-caused neglected tropical diseases (sleeping sickness, Chagas disease and leishmaniasis) relies exclusively on pharmacological treatments. Current drugs against them are scarce, old and exhibit disadvantages, such as adverse effects, parenteral administration, chemical instability and high costs which are often unaffordable for endemic low-income countries. Discoveries of new pharmacological entities for the treatment of these diseases are scarce, since most of the big pharmaceutical companies find this market unattractive. In order to fill the pipeline of compounds and replace existing ones, highly translatable drug screening platforms have been developed in the last two decades. Thousands of molecules have been tested, including nitroheterocyclic compounds, such as benznidazole and nifurtimox, which had already provided potent and effective effects against Chagas disease. More recently, fexinidazole has been added as a new drug against African trypanosomiasis. Despite the success of nitroheterocycles, they had been discarded from drug discovery campaigns due to their mutagenic potential, but now they represent a promising source of inspiration for oral drugs that can replace those currently on the market. The examples provided by the trypanocidal activity of fexinidazole and the promising efficacy of the derivative DNDi-0690 against leishmaniasis seem to open a new window of opportunity for these compounds that were discovered in the 1960s. In this review, we show the current uses of nitroheterocycles and the novel derived molecules that are being synthesized against these neglected diseases.

Activity of poly(methacrylic acid)-silver nanoparticles on fluconazole-resistant Candida albicans strains: Synergistic and cytotoxic effects.

AIMS: To synthesize and evaluate the antifungal activity of poly(methacrylic acid)-silver nanoparticles (PMAA-AgNPs) against nine Candida albicans isolated from clinical specimens. METHODS AND RESULTS: The effects of PMAA-AgNPs-fluconazole combination was analysed by checkerboard methodology. The synergistic potential of PMAA-AgNPs-fluconazole was determined by the fractional inhibitory concentration index (FICI). The inhibition of germ tube formation and the determination of PMAA-AgNPs cytotoxicity were also performed. All C. albicans strains were susceptible to PMAA-AgNPs and resistant to fluconazole. PMAA-AgNPs at subinhibitory concentrations restored the susceptibility of resistant C. albicans to fluconazole, whose FICI ranged from 0.3 to 0.5. The synergistic interaction of the combination was observed in eight of nine strains. The PMAA-AgNPs-fluconazole combination was also able to inhibit the germ tube formation. PMAA-AgNPs showed a dose-dependent decrease in viability for cells tested, with 50% cytotoxic concentration (CC50 ) values of 6.5, 4.9 and 6.8 µg ml-1 for macrophages, fibroblasts and Vero cells, respectively. CONCLUSIONS: This study demonstrated that, in general, PMAA-AgNPs acts synergistically in combination with fluconazole, inhibiting fluconazole-resistant C. albicans strains. PMAA-AgNPs-fluconazole combination was also able to inhibit germ tube formation, an important virulence factor. Inhibitory effect of PMAA-AgNPs alone or in combination was higher in C. albicans than in mammalian cells. SIGNIFICANCE AND IMPACT OF STUDY: This study shows the potential of PMAA-AgNPs combined with fluconazole to inhibit fluconazole-resistant C. albicans strains.

Leishmanicidal and cytotoxic activity of essential oil from the fruit peel of Myrciaria floribunda (H. West ex Willd.) O. Berg: Molecular docking and molecular dynamics simulations of its major constituent onto Leishmania enzyme targets.

Cutaneous Leishmaniasis (CL) is a neglected disease characterized by highest morbidity rates worldwide. The available treatment for CL has several limitations including serious side effects and resistance to the treatment. Herein we aimed to evaluate the activity of essential oil from the peel of Myrciaria floribunda fruits (MfEO) on Leishmania amazonensis. The cytotoxic potential of MfEO on host mammalian cells was evaluated by MTT. The in vitro leishmanicidal effects of MfEO were investigated on the promastigote and intracellular amastigote forms. The ultrastructural changes induced by MfEO were evaluated by Scanning Electron Microscopy (SEM). The molecular docking of the major compounds δ-Cadinene, γ-Cadinene, γ-Muurolene, α-Selinene, α-Muurolene and (E)-Caryophyllene onto the enzymes trypanothione reductase (TreR) and sterol 14-alpha demethylase (C14DM) were performed. Our results showed that MfEO presented moderate cytotoxicity for Vero cells and macrophages. The MfEO inhibited the growth of promastigote and the survival of intracellular amastigotes, in a dose- and time- dependent way. The MfEO presented high selectivity towards amastigote forms, being 44.1 times more toxic for this form than to macrophages. Molecular docking analysis showed that the major compounds of MfEO interact with Leishmania enzymes and that δ-Cadinene (δ-CAD) presented favorable affinity energy values over TreR and C14DM enzymes, when compared with the other major constituents. Molecular dynamics (MD) simulation studies revealed a stable binding of δ-CAD with lowest binding free energy values in MMGBSA assay. Our results suggested that δ-CAD may be a potent inhibitor of TreR and C14DM enzymes. Communicated by Ramaswamy H. Sarma.

Identification of 1,2,3-triazole-phthalimide derivatives as potential drugs against COVID-19: a virtual screening, docking and molecular dynamic study.

In this work we aimed to perform an in silico predictive screening, docking and molecular dynamic study to identify 1,2,3-triazole-phthalimide derivatives as drug candidates against SARS-CoV-2. The in silico prediction of pharmacokinetic and toxicological properties of hundred one 1,2,3-triazole-phtalimide derivatives, obtained from SciFinder® library, were investigated. Compounds that did not show good gastrointestinal absorption, violated the Lipinski's rules, proved to be positive for the AMES test, and showed to be hepatotoxic or immunotoxic in our ADMET analysis, were filtered out of our study. The hit compounds were further subjected to molecular docking on SARS-CoV-2 target proteins. The ADMET analysis revealed that 43 derivatives violated the Lipinski's rules and 51 other compounds showed to be positive for the toxicity test. Seven 1,2,3-triazole-phthalimide derivatives (A7, A8, B05, E35, E38, E39, and E40) were selected for molecular docking and MFCC-ab initio analysis. The results of molecular docking pointed the derivative E40 as a promising compound interacting with multiple target proteins of SARS-CoV-2. The complex E40-Mpro was found to have minimum binding energy of -10.26 kcal/mol and a general energy balance, calculated by the quantum mechanical analysis, of -8.63 eV. MD simulation and MMGBSA calculations confirmed that the derivatives E38 and E40 have high binding energies of -63.47 ± 3 and -63.31 ± 7 kcal/mol against SARS-CoV-2 main protease. In addition, the derivative E40 exhibited excellent interaction values and inhibitory potential against SAR-Cov-2 main protease and viral nucleocapsid proteins, suggesting this derivative as a potent antiviral for the treatment and/or prophylaxis of COVID-19.Communicated by Ramaswamy H. Sarma.

A new biocompatible silver/polypyrrole composite with in vitro antitumor activity.

We used an in situ chemical oxidation method to prepare a new composite of silver nanoparticles (AgNPs) with polypyrrole (PPy), whose properties were optimized through a 23-factorial design of the synthesis conditions. The successful formation of the AgNPs/PPy composite was confirmed by UV-Visible and FTIR spectroscopies. Transmission electron microscopy revealed the presence of AgNPs smaller than 100 nm, dispersed into the PPy matrix. This hybrid composite exhibits a blue fluorescence emission after excitation in the ultraviolet region. In MTT assays, the AgNPs/PPy composite exhibited low cytotoxicity toward non-tumoral cell lines (fibroblast, Vero, and macrophages) and selectively inhibited the viability of HeLa cells. The AgNPs/PPy composite induces ultrastructural changes in HeLa cells that are consistent with the noticeable selectivity exhibited toward them when compared to its action against non-tumoral cell lineages. Also, the AgNPs/PPy exhibited a hemolytic activity below 14% for all blood groups tested, at concentrations up to 125 µg/mL. These results suggest that the AgNPs/PPy composite has a promising potential for use as an antitumoral agent.

Effects of nasal aspiration by the Proetz® method in pediatric patients with sinusitis.

OBJECTIVE: To characterize the effects of nasal aspiration with Proetz® in peak nasal inspiratory flow (PNIF) in pediatric sinusitis (PS) patients with nasal obstruction. METHODS: This is a non-randomized descriptive-analytical clinical trial with a quantitative approach. The sample comprised 30 children. Initially, the PNIF was measured and the Visual Analogical Scale (VAS) was used for nasal obstruction, followed by the nasal aspiration procedure. The SNOT-22 questionnaire was applied to the legal guardian of each child, and one week later, it was reapplied for the sake of follow-up. RESULTS: 16 (53.3%) patients were females and 14 (46.7%) were males, with an average age of 6.4±1.8 years (between 4 and 10 years of age). Analyses of the VAS for obstruction before the intervention revealed that 10 of the participants (33.3%) presented moderate levels, and 20 of them (66.7%) severe levels. However, after the Proetz® method was applied, all the samples (n=30) had mild levels. The PNIF significantly increased after the technique was used, with an improvement of 23.4% in mean values. There was no significant correlation between the VAS and the PNIF. CONCLUSION: Nasal aspiration with the Proetz® method significantly improved the clinical condition of sinusitis patients with nasal obstruction according to the visual analogical scale, the PNIF, and the SNOT-22 questionnaire. No correlation between the VAS and the PNIF could be found. The study confirms the importance of non-pharmacological interventions in the treatment of sinusitis in children, thus resulting in an improvement in their quality of life.

Antileishmanial activity of 4-phenyl-1-[2-(phthalimido-2-yl)ethyl]-1H-1,2,3-triazole (PT4) derivative on Leishmania amazonensis and Leishmania braziliensis: In silico ADMET, in vitro activity, docking and molecular dynamic simulations.

Organic compounds obtained by click chemistry reactions have demonstrated a broad spectrum of biological activities being widely applied for the development of molecules against pathogens of medical and veterinary importance. Cutaneous leishmaniasis (CL), caused by intracellular protozoa parasite of genus Leishmania, comprises a complex of clinical manifestations that affect the skin and mucous membranes. The available drugs for the treatment are toxic and costly, with long periods of treatment, and the emergence of resistant strains has been reported. In this study we investigated the in vitro effects of a phthalimide-1,2,3-triazole derivative, the 4-Phenyl-1-[2-(phthalimido-2-yl)ethyl]-1H-1,2,3-triazole (PT4) obtained by click chemistry, on mammalian cells and on L. amazonensis and L. braziliensis, the causative agents of CL in Brazil. In silico ADMET evaluation of PT4 showed that this molecule has good pharmacokinetic properties with no violation of Lipinski's rules. The in vitro assays showed that PT4 was more selective for both Leishmania species than to mammalian cells. This compound also presented low cytotoxicity to mammalian cells with CC50 > 500 µM. Treatment of promastigote forms with different concentrations of PT4 resulted in ultrastructural alterations, such as plasma membrane wrinkling, shortening of cell body, increased cell volume and cell rupture. The molecular dynamic simulations showed that PT4 interacts with Lanosterol 14 α-demethylase from Leishmania, an essential enzyme of lipid synthesis pathway in this parasite. Our results demonstrated PT4 was effective against both species of Leishmania. PT4 caused a decrease of mitochondrial membrane potential and increased production of reactive oxygen species, which may lead to parasite death. Taken together, our results pointed PT4 as promissing therapeutic agent against CL.

Effects of nasal aspiration by the Proetz® method in pediatric patients with sinusitis

SUMMARY OBJECTIVE: To characterize the effects of nasal aspiration with Proetz® in peak nasal inspiratory flow (PNIF) in pediatric sinusitis (PS) patients with nasal obstruction. METHODS: This is a non-randomized descriptive-analytical clinical trial with a quantitative approach. The sample comprised 30 children. Initially, the PNIF was measured and the Visual Analogical Scale (VAS) was used for nasal obstruction, followed by the nasal aspiration procedure. The SNOT-22 questionnaire was applied to the legal guardian of each child, and one week later, it was reapplied for the sake of follow-up. RESULTS: 16 (53.3%) patients were females and 14 (46.7%) were males, with an average age of 6.4±1.8 years (between 4 and 10 years of age). Analyses of the VAS for obstruction before the intervention revealed that 10 of the participants (33.3%) presented moderate levels, and 20 of them (66.7%) severe levels. However, after the Proetz® method was applied, all the samples (n=30) had mild levels. The PNIF significantly increased after the technique was used, with an improvement of 23.4% in mean values. There was no significant correlation between the VAS and the PNIF. CONCLUSION: Nasal aspiration with the Proetz® method significantly improved the clinical condition of sinusitis patients with nasal obstruction according to the visual analogical scale, the PNIF, and the SNOT-22 questionnaire. No correlation between the VAS and the PNIF could be found. The study confirms the importance of non-pharmacological interventions in the treatment of sinusitis in children, thus resulting in an improvement in their quality of life.

RESUMO OBJETIVO: Caracterizar os efeitos da aspiração nasal com Proetz® no pico do fluxo inspiratório nasal (Pnif) em pacientes com sinusite pediátrica (SP) com obstrução nasal. MÉTODOS: Trata-se de um ensaio clínico analítico descritivo, não randomizado, com abordagem quantitativa. A amostra foi composta por 30 crianças. Inicialmente, o Pnif foi medido e a escala visual analógica (EVA) foi utilizada para obstrução nasal, seguida do procedimento de aspiração nasal. O questionário Snot-22 foi aplicado ao responsável legal de cada criança e, uma semana depois, foi reaplicado para fins de acompanhamento. RESULTADOS: Dezesseis (53,3%) pacientes eram do sexo feminino e 14 (46,7%) do sexo masculino, com idade média de 6,4±1,8 anos (entre 4 e 10 anos). A análise da EVA para obstrução antes da intervenção revelou que dez dos participantes (33,3%) apresentaram níveis moderados e 20 deles (66,7%), níveis graves. No entanto, após a aplicação do método Proetz®, todas as amostras (n=30) apresentaram níveis leves. O Pnif aumentou significativamente após a utilização da técnica, com uma melhoria de 23,4% nos valores médios. Não houve correlação significativa entre EVA e Pnif. CONCLUSÃO: A aspiração nasal com o método Proetz® melhorou significativamente o quadro clínico de pacientes com sinusite com obstrução nasal, de acordo com a escala visual analógica, o Pnif e o questionário Snot-22. Não foi encontrada correlação entre EVA e Pnif. O estudo confirma a importância de intervenções não farmacológicas no tratamento da sinusite em crianças, resultando em melhoria na sua qualidade de vida.