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1.
Molecules ; 26(16)2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34443484

RESUMO

The COVID-19 outbreak has rapidly spread on a global scale, affecting the economy and public health systems throughout the world. In recent years, peptide-based therapeutics have been widely studied and developed to treat infectious diseases, including viral infections. Herein, the antiviral effects of the lysine linked dimer des-Cys11, Lys12,Lys13-(pBthTX-I)2K ((pBthTX-I)2K)) and derivatives against SARS-CoV-2 are reported. The lead peptide (pBthTX-I)2K and derivatives showed attractive inhibitory activities against SARS-CoV-2 (EC50 = 28-65 µM) and mostly low cytotoxic effect (CC50 > 100 µM). To shed light on the mechanism of action underlying the peptides' antiviral activity, the Main Protease (Mpro) and Papain-Like protease (PLpro) inhibitory activities of the peptides were assessed. The synthetic peptides showed PLpro inhibition potencies (IC50s = 1.0-3.5 µM) and binding affinities (Kd = 0.9-7 µM) at the low micromolar range but poor inhibitory activity against Mpro (IC50 > 10 µM). The modeled binding mode of a representative peptide of the series indicated that the compound blocked the entry of the PLpro substrate toward the protease catalytic cleft. Our findings indicated that non-toxic dimeric peptides derived from the Bothropstoxin-I have attractive cellular and enzymatic inhibitory activities, thereby suggesting that they are promising prototypes for the discovery and development of new drugs against SARS-CoV-2 infection.


Assuntos
Venenos de Crotalídeos/química , Dimerização , Papaína/antagonistas & inibidores , Peptídeos/química , Peptídeos/farmacologia , SARS-CoV-2/enzimologia , Antivirais/química , Antivirais/metabolismo , Antivirais/farmacologia , Simulação de Acoplamento Molecular , Papaína/química , Papaína/metabolismo , Peptídeos/metabolismo , Inibidores de Proteases/química , Inibidores de Proteases/metabolismo , Inibidores de Proteases/farmacologia , Conformação Proteica , SARS-CoV-2/efeitos dos fármacos
2.
J Chem Inf Model ; 61(9): 4224-4235, 2021 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-34387990

RESUMO

With the rapidly evolving SARS-CoV-2 variants of concern, there is an urgent need for the discovery of further treatments for the coronavirus disease (COVID-19). Drug repurposing is one of the most rapid strategies for addressing this need, and numerous compounds have already been selected for in vitro testing by several groups. These have led to a growing database of molecules with in vitro activity against the virus. Machine learning models can assist drug discovery through prediction of the best compounds based on previously published data. Herein, we have implemented several machine learning methods to develop predictive models from recent SARS-CoV-2 in vitro inhibition data and used them to prioritize additional FDA-approved compounds for in vitro testing selected from our in-house compound library. From the compounds predicted with a Bayesian machine learning model, lumefantrine, an antimalarial was selected for testing and showed limited antiviral activity in cell-based assays while demonstrating binding (Kd 259 nM) to the spike protein using microscale thermophoresis. Several other compounds which we prioritized have since been tested by others and were also found to be active in vitro. This combined machine learning and in vitro testing approach can be expanded to virtually screen available molecules with predicted activity against SARS-CoV-2 reference WIV04 strain and circulating variants of concern. In the process of this work, we have created multiple iterations of machine learning models that can be used as a prioritization tool for SARS-CoV-2 antiviral drug discovery programs. The very latest model for SARS-CoV-2 with over 500 compounds is now freely available at www.assaycentral.org.


Assuntos
COVID-19 , SARS-CoV-2 , Teorema de Bayes , Humanos , Aprendizado de Máquina , Simulação de Acoplamento Molecular
3.
J Chem Inf Model ; 61(8): 3804-3813, 2021 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-34286575

RESUMO

Yellow fever (YF) is an acute viral hemorrhagic disease transmitted by infected mosquitoes. Large epidemics of YF occur when the virus is introduced into heavily populated areas with high mosquito density and low vaccination coverage. The lack of a specific small molecule drug treatment against YF as well as for homologous infections, such as zika and dengue, highlights the importance of these flaviviruses as a public health concern. With the advancement in computer hardware and bioactivity data availability, new tools based on machine learning methods have been introduced into drug discovery, as a means to utilize the growing high throughput screening (HTS) data generated to reduce costs and increase the speed of drug development. The use of predictive machine learning models using previously published data from HTS campaigns or data available in public databases, can enable the selection of compounds with desirable bioactivity and absorption, distribution, metabolism, and excretion profiles. In this study, we have collated cell-based assay data for yellow fever virus from the literature and public databases. The data were used to build predictive models with several machine learning methods that could prioritize compounds for in vitro testing. Five molecules were prioritized and tested in vitro from which we have identified a new pyrazolesulfonamide derivative with EC50 3.2 µM and CC50 24 µM, which represents a new scaffold suitable for hit-to-lead optimization that can expand the available drug discovery candidates for YF.

4.
Virus Res ; 299: 198388, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-33887282

RESUMO

The 2015/16 Zika virus (ZIKV) epidemic led to almost 1 million confirmed cases in 84 countries and was associated to the development of congenital microcephaly and Guillain-Barré syndrome. More recently, a ZIKV African lineage was identified in Brazil raising concerns about a future outbreak. The long-term consequences of viral infection emphasizes the need for the development of effective anti-ZIKV drugs. In this study, we developed and characterized a ZIKV replicon cell line for the screening of viral replication inhibitors. The replicon system was developed by engineering the IRES-Neo cassette into the 3' UTR terminus of the ZIKV Rluc DNA construct. After in vitro transcription, replicon RNA was used to transfect BHK-21 cells, that were selected with G418, thus generating the BHK-21-RepZIKV_IRES-Neo cell line. Through this replicon-based cell system, we identified two molecules with potent anti-ZIKV activities, an imidazonaphthyridine and a riminophenazine, both from the MMV/DNDi Pandemic Response Box library of 400 drug-like compounds. The imidazonaphthyridine, known as RO8191, showed remarkable selectivity against ZIKV, while the riminophenazine, the antibiotic Clofazimine, could act as a non-nucleoside analog inhibitor of viral RNA-dependent RNA polymerase (RdRp), as evidenced both in vitro and in silico. The data showed herein supports the use of replicon-based assays in high-throughput screening format as a biosafe and reliable tool for antiviral drug discovery.

5.
Nat Prod Res ; : 1-7, 2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33703954

RESUMO

Malaria is an infectious illness, affecting vulnerable populations in Third World countries. Inspired by natural products, indole alkaloids have been used as a nucleus to design new antimalarial drugs. So, eighteen oxindole derivatives, aza analogues were obtained with moderate to excellent yields. Also, the saturated derivatives of oxindole and aza derivatives via H2/Pd/C reduction were obtained in good yields, leading to racemic mixtures of each compound. Next, the inhibitory activity against P. falciparum of 18 compounds were tested, founding six compounds with IC50 < 20 µM. The most active of these compounds was 8c; however, their unsaturated derivative 7c was inactive. Then, a structure-activity relationship analysis was done, founding that focused LUMO lobe on the specific molecular zone is related to inhibitory activity against P. falciparum. Finally, we found a potential inhibition of lactate dehydrogenase by oxindole derivatives, using molecular docking virtual screening.

6.
Bioorg Chem ; 109: 104719, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33636437

RESUMO

Although the widespread epidemic of Zika virus (ZIKV) and its neurological complications are well-known there are still no approved drugs available to treat this arboviral disease or vaccine to prevent the infection. Flavonoids from Pterogyne nitens have already demonstrated anti-flavivirus activity, although their target is unknown. In this study, we virtually screened an in-house database of 150 natural and semi-synthetic compounds against ZIKV NS2B-NS3 protease (NS2B-NS3p) using docking-based virtual screening, as part of the OpenZika project. As a result, we prioritized three flavonoids from P. nitens, quercetin, rutin and pedalitin, for experimental evaluation. We also used machine learning models, built with Assay Central® software, for predicting the activity and toxicity of these flavonoids. Biophysical and enzymatic assays generally agreed with the in silico predictions, confirming that the flavonoids inhibited ZIKV protease. The most promising hit, pedalitin, inhibited ZIKV NS2B-NS3p with an IC50 of 5 µM. In cell-based assays, pedalitin displayed significant activity at 250 and 500 µM, with slight toxicity in Vero cells. The results presented here demonstrate the potential of pedalitin as a candidate for hit-to-lead (H2L) optimization studies towards the discovery of antiviral drug candidates to treat ZIKV infections.


Assuntos
Antivirais/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Proteínas Virais/antagonistas & inibidores , Zika virus/metabolismo , Animais , Antivirais/química , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Flavonas/farmacologia , Aprendizado de Máquina , Modelos Moleculares , Simulação de Acoplamento Molecular , Conformação Proteica , Quercetina/farmacologia , Rutina/farmacologia , Serina Endopeptidases , Células Vero
7.
Viruses ; 12(6)2020 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-32486283

RESUMO

Single-stranded positive RNA ((+) ssRNA) viruses include several important human pathogens. Some members are responsible for large outbreaks, such as Zika virus, West Nile virus, SARS-CoV, and SARS-CoV-2, while others are endemic, causing an enormous global health burden. Since vaccines or specific treatments are not available for most viral infections, the discovery of direct-acting antivirals (DAA) is an urgent need. Still, the low-throughput nature of and biosafety concerns related to traditional antiviral assays hinders the discovery of new inhibitors. With the advances of reverse genetics, reporter replicon systems have become an alternative tool for the screening of DAAs. Herein, we review decades of the use of (+) ssRNA viruses replicon systems for the discovery of antiviral agents. We summarize different strategies used to develop those systems, as well as highlight some of the most promising inhibitors identified by the method. Despite the genetic alterations introduced, reporter replicons have been shown to be reliable systems for screening and identification of viral replication inhibitors and, therefore, an important tool for the discovery of new DAAs.


Assuntos
Antivirais/farmacologia , Descoberta de Drogas/métodos , Genes Reporter/fisiologia , Vírus de RNA/efeitos dos fármacos , Replicon/fisiologia , Animais , Antivirais/química , Linhagem Celular , Chlorocebus aethiops , Cricetinae , Humanos , Vírus de RNA/genética , Transfecção , Células Vero
8.
Biochim Biophys Acta Gen Subj ; 1864(4): 129521, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31931019

RESUMO

BACKGROUND: The Yellow Fever virus (YFV) is transmitted by mosquitos and causes an infection with symptoms including fever, headaches and nausea. In 20-50% of the cases, the disease may evolve to a visceral stage, reaching high mortality rates. YFV NS2B-NS3 protease has been identified as an important drug target. METHODS: Herein, we describe the crystal structure of the NS2B-NS3 protease from the 2017 YFV Brazilian circulating strain using X-ray crystallography. Furthermore, we used a combination of biochemical and biophysical assays to characterize the enzyme and investigate the impact of the polymorphisms observed in different YFV circulating strains. RESULTS: Surprisingly, the crystal structure of YFV protease seems to adopt the closed conformation without the presence of a binding partner. Although D88E and K121R mutants exhibited a lower affinity for the substrate, both revealed to be more processive, resulting in a similar catalytic efficiency in relation to the WT protease. Still, both mutants showed an accentuated decrease in stability when compared with the WT. CONCLUSIONS: The crystal structure of YFV NS2B-NS3 in closed conformation might be an important tool for the development of new drugs, as well as understanding the activation mechanism of viral proteases. Biochemical analyses indicate that the NS2B-NS3 protease of the circulating strain of YFV is more stable than previous strains. GENERAL SIGNIFICANCE: The YFV NS2B-NS3 protease is the first flaviviral structure described in its closed conformation when in a free form, implying that external factors might induce the activation of the enzyme.


Assuntos
Polimorfismo de Nucleotídeo Único/genética , Proteínas não Estruturais Virais/química , Proteínas não Estruturais Virais/genética , Vírus da Febre Amarela/enzimologia , Brasil , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , RNA Helicases/química , RNA Helicases/genética , RNA Helicases/metabolismo , Serina Endopeptidases/química , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Proteínas não Estruturais Virais/metabolismo
9.
J Chem Inf Model ; 60(2): 1028-1041, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-31765144

RESUMO

A virtual screening conducted with nearly 4 000 000 compounds from lead-like and fragment-like subsets enabled the identification of a small-molecule inhibitor (1) of the Trypanosoma cruzi cruzain enzyme, a validated drug target for Chagas disease. Subsequent comprehensive structure-based drug design and structure-activity relationship studies led to the discovery of carbamoyl imidazoles as potent, reversible, and competitive cruzain inhibitors. The most potent carbamoyl imidazole inhibitor (45) exhibited high affinity with a Ki value of 20 nM, presenting both in vitro and in vivo activity against T. cruzi. Furthermore, the most promising compounds reduced parasite burden in vivo and showed no toxicity at a dose of 100 mg/kg. These carbamoyl imidazoles are structurally attractive, nonpeptidic, and easy to prepare and synthetically modify. Finally, these results further advance our understanding of the noncovalent mode of inhibition of this pharmaceutically relevant enzyme, building strong foundations for drug discovery efforts.


Assuntos
Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/farmacologia , Desenho de Fármacos , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Cisteína Endopeptidases/química , Modelos Moleculares , Conformação Proteica , Proteínas de Protozoários/química , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia
10.
Sci Rep ; 9(1): 17703, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-31776405

RESUMO

Zika virus (ZIKV) is a mosquito-transmitted Flavivirus, originally identified in Uganda in 1947 and recently associated with a large outbreak in South America. Despite extensive efforts there are currently no approved antiviral compounds for treatment of ZIKV infection. Here we describe the antiviral activity of diarylamines derived from anthranilic acid (FAMs) against ZIKV. A synthetic FAM (E3) demonstrated anti-ZIKV potential by reducing viral replication up to 86%. We analyzed the possible mechanisms of action of FAM E3 by evaluating the intercalation of this compound into the viral dsRNA and its interaction with the RNA polymerase of bacteriophage SP6. However, FAM E3 did not act by these mechanisms. In silico results predicted that FAM E3 might bind to the ZIKV NS3 helicase suggesting that this protein could be one possible target of this compound. To test this, the thermal stability and the ATPase activity of the ZIKV NS3 helicase domain (NS3Hel) were investigated in vitro and we demonstrated that FAM E3 could indeed bind to and stabilize NS3Hel.


Assuntos
Antivirais/farmacologia , Replicação Viral , Zika virus/efeitos dos fármacos , ortoaminobenzoatos/farmacologia , Aminas/química , Animais , Antivirais/síntese química , Sítios de Ligação , Chlorocebus aethiops , Ligação Proteica , Serina Endopeptidases/química , Serina Endopeptidases/metabolismo , Células Vero , Proteínas Virais/química , Proteínas Virais/metabolismo , Zika virus/fisiologia , ortoaminobenzoatos/síntese química
11.
Curr Opin Struct Biol ; 59: 65-72, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-30954758

RESUMO

With almost half of the world population living at risk, tropical infectious diseases cause millions of deaths every year in developing countries. Considering the lack of economic prospects for investment in this field, approaches aiming the rational design of compounds, such as structure-based drug discovery (SBDD), fragment screening, target-based drug discovery, and drug repurposing are of special interest. Herein, we focused in the advances on the field of SBDD targeting arboviruses such as dengue, yellow fever, zika and chikungunya enzymes of the RNA replication complex (RC) and enzymes involved in a variety of pathways essential to ensure parasitic survival in the host, for malaria, Chagas e leishmaniasis diseases. We also highlighted successful examples such as promising new inhibitors and molecules already in preclinical/clinical phase tests, major gaps in the field and perspectives for the future of drug design for tropical diseases.


Assuntos
Antiparasitários/química , Antivirais/química , Inibidores Enzimáticos/química , Enzimas/química , Proteínas de Protozoários/química , Relação Quantitativa Estrutura-Atividade , Proteínas Virais/química , Antiparasitários/farmacologia , Antivirais/farmacologia , Inibidores Enzimáticos/farmacologia , Antagonistas do Ácido Fólico/química , Antagonistas do Ácido Fólico/farmacologia , Humanos , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Proteínas de Protozoários/metabolismo , Tetra-Hidrofolato Desidrogenase/química , Proteínas Virais/metabolismo
12.
Malar J ; 18(1): 447, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31888654

RESUMO

BACKGROUND: Artemisinin-based combination therapy (ACT) is used as the first-line treatment of uncomplicated malaria caused by the Plasmodium falciparum parasite and chloroquine-resistant Plasmodium vivax parasites. Evidence of resistance to ACT has been reported in Cambodia, and without new and effective anti-malarial agents, malaria burden and mortality will rise. METHODS: The used MolPrint 2D fingerprints and the Tanimoto similarity index were used to perform a structural similarity search within the Malaria Box collection to select diverse molecular scaffolds that are different from artesunate. Next, the inhibitory potency against the P. falciparum 3D7 strain (SYBR Green I inhibition assay) and the cytotoxicity against HepG2 cells (MTT and neutral red assays) were evaluated. Then, the speed of action, the combination profile of selected inhibitors with artesunate, and the P. berghei in vivo activity of the best compounds were assessed. RESULTS: A set of 11 structurally diverse compounds from the Malaria Box with a similarity threshold of less than 0.05 was selected and compared with artesunate. The in vitro inhibitory activity of each compound confirmed the reported potencies (IC50 values ranging from 0.005 to 1 µM). The cytotoxicity of each selected compound was evaluated and used to calculate the selectivity index (SI values ranging from 15.1 to 6100). Next, both the speed of action and the combination profile of each compound with artesunate was assessed. Acridine, thiazolopyrimidine, quinoxaline, benzimidazole, thiophene, benzodiazepine, isoxazole and pyrimidoindole derivatives showed fast in vitro inhibitory activity of parasite growth, whereas hydrazinobenzimidazole, indenopyridazinone and naphthalenone derivatives were slow-acting in vitro inhibitors. Combinatory profile evaluation indicated that thiazolopyrimidinone and benzodiazepine derivatives have an additive profile, suggesting that the combination of these inhibitors with artesunate is favourable for in vitro inhibitory activity. The remaining compounds showed an antagonistic combinatory profile with artesunate. The collected data indicated that the indenopyridazinone derivative, a bc1 complex inhibitor, had a similar association profile in combination with proguanil when compared to atovaquone combined with proguanil, thereby corroborating the correlation between the molecular target and the combination profile. Lastly, the in vivo activity of the thiazolopyrimidinone and benzodiazepine derivatives were assessed. Both compounds showed oral efficacy at 50 mg/kg in a mouse model of Plasmodium berghei malaria (64% and 40% reduction in parasitaemia on day 5 post-infection, respectively). CONCLUSIONS: The findings in this paper shed light on the relationship among the speed of action, molecular target and combinatory profile and identified new hits with in vivo activity as candidates for anti-malarial combination therapy.


Assuntos
Antimaláricos/farmacologia , Artesunato/farmacologia , Combinação de Medicamentos , Plasmodium berghei/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Antimaláricos/toxicidade , Artesunato/toxicidade , Células Hep G2 , Humanos , Malária Falciparum/prevenção & controle , Testes de Toxicidade
13.
Curr Med Chem ; 26(23): 4380-4402, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-28875841

RESUMO

Malaria remains a major health problem, especially because of the emergence of resistant P. falciparum strains to artemisinin derivatives. In this context, safe and affordable antimalarial drugs are desperately needed. New proteins have been investigated as molecular targets for research and development of innovative compounds with welldefined mechanism of action. In this review, we highlight genetically and clinically validated plasmodial proteins as drug targets for the next generation of therapeutics. The enzymes described herein are involved in hemoglobin hydrolysis, the invasion process, elongation factors for protein synthesis, pyrimidine biosynthesis, post-translational modifications such as prenylation, phosphorylation and histone acetylation, generation of ATP in mitochondrial metabolism and aminoacylation of RNAs. Significant advances on proteomics, genetics, structural biology, computational and biophysical methods provided invaluable molecular and structural information about these drug targets. Based on this, several strategies and models have been applied to identify and improve lead compounds. This review presents the recent progresses in the discovery of antimalarial drug candidates, highlighting the approaches, challenges, and perspectives to deliver affordable, safe and low single-dose medicines to treat malaria.


Assuntos
Antimaláricos/farmacologia , Descoberta de Drogas , Malária/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Animais , Antimaláricos/química , Humanos
14.
J Med Chem ; 61(13): 5547-5568, 2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-29879353

RESUMO

We report the discovery of marinoquinoline (3 H-pyrrolo[2,3- c]quinoline) derivatives as new chemotypes with antiplasmodial activity. We evaluated their inhibitory activities against P. falciparum and conducted a structure-activity relationship study, focusing on improving their potency and maintaining low cytotoxicity. Next, we devised quantitative structure-activity relationship (QSAR) models, which we prospectively validated, to discover new analogues with enhanced potency. The most potent compound, 50 (IC503d7 = 39 nM; IC50K1 = 41 nM), is a fast-acting inhibitor with dual-stage (blood and liver) activity. The compound showed considerable selectivity (SI > 6410), an additive effect when administered in combination with artesunate, excellent tolerability in mice (all mice survived after an oral treatment with a 1000 mg/kg dose), and oral efficacy at 50 mg/kg in a mouse model of P. berghei malaria (62% reduction in parasitemia on day 5 postinfection); thus, compound 50 was considered a lead compound for the discovery of new antimalarial agents.


Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Desenho de Fármacos , Plasmodium falciparum/efeitos dos fármacos , Quinolinas/química , Quinolinas/farmacologia , Animais , Camundongos , Modelos Moleculares , Conformação Molecular , Relação Quantitativa Estrutura-Atividade
15.
An Acad Bras Cienc ; 90(1 Suppl 1): 645-661, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29451603

RESUMO

Scientific and technological breakthroughs have compelled the current players in drug discovery to increasingly incorporate knowledge-based approaches. This evolving paradigm, which has its roots attached to the recent advances in medicinal chemistry, molecular and structural biology, has unprecedentedly demanded the development of up-to-date computational approaches, such as bio- and chemo-informatics. These tools have been pivotal to catalyzing the ever-increasing amount of data generated by the molecular sciences, and to converting the data into insightful guidelines for use in the research pipeline. As a result, ligand- and structure-based drug design have emerged as key pathways to address the pharmaceutical industry's striking demands for innovation. These approaches depend on a keen integration of experimental and molecular modeling methods to surmount the main challenges faced by drug candidates - in vivo efficacy, pharmacodynamics, metabolism, pharmacokinetics and safety. To that end, the Laboratório de Química Medicinal e Computacional (LQMC) of the Universidade de São Paulo has developed forefront research on highly prevalent and life-threatening neglected tropical diseases and cancer. By taking part in global initiatives for pharmaceutical innovation, the laboratory has contributed to the advance of these critical therapeutic areas through the use of cutting-edge strategies in medicinal chemistry.


Assuntos
Antineoplásicos/química , Química Farmacêutica , Descoberta de Drogas/métodos , Doenças Negligenciadas/tratamento farmacológico , Neoplasias/tratamento farmacológico , Tripanossomicidas/química , Doença de Chagas/tratamento farmacológico , Humanos , Esquistossomose/tratamento farmacológico , Medicina Tropical/tendências
16.
J Nat Prod ; 81(1): 188-202, 2018 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-29297684

RESUMO

The isolation and identification of a series of new pseudoceratidine (1) derivatives from the sponge Tedania brasiliensis enabled the evaluation of their antiparasitic activity against Plasmodium falciparum, Leishmania (Leishmania) amazonensis, Leishmania (Leishmania) infantum, and Trypanosoma cruzi, the causative agents of malaria, cutaneous leishmaniasis, visceral leishmaniasis, and Chagas disease, respectively. The new 3-debromopseudoceratidine (4), 20-debromopseudoceratidine (5), 4-bromopseudoceratidine (6), 19-bromopseudoceratidine (7), and 4,19-dibromopseudoceratidine (8) are reported. New tedamides A-D (9-12), with an unprecedented 4-bromo-4-methoxy-5-oxo-4,5-dihydro-1H-pyrrole-2-carboxamide moiety, are also described. Compounds 4 and 5, 6 and 7, 9 and 10, and 11 and 12 have been isolated as pairs of inseparable structural isomers differing in their sites of bromination or oxidation. Tedamides 9+10 and 11+12 were obtained as optically active pairs, indicating an enzymatic formation rather than an artifactual origin. N12-Acetylpseudoceratidine (2) and N12-formylpseudoceratidine (3) were obtained by derivatization of pseudoceratidine (1). The antiparasitic activity of pseudoceratidine (1) led us to synthesize 23 derivatives (16, 17, 20, 21, 23, 25, 27-29, 31, 33, 35, 38, 39, 42, 43, 46, 47, 50, and 51) with variations in the polyamine chain and aromatic moiety in sufficient amounts for biological evaluation in antiparasitic assays. The measured antimalarial activity of pseudoceratidine (1) and derivatives 4, 5, 16, 23, 25, 31, and 50 provided an initial SAR evaluation of these compounds as potential leads for antiparasitics against Leishmania amastigotes and against P. falciparum. The results obtained indicate that pseudoceratidine represents a promising scaffold for the development of new antimalarial drugs.


Assuntos
Alcaloides/química , Alcaloides/farmacologia , Antiparasitários/química , Antiparasitários/farmacologia , Poríferos/química , Animais , Antimaláricos/química , Antimaláricos/farmacologia , Antiprotozoários/química , Antiprotozoários/farmacologia , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Testes de Sensibilidade Parasitária , Plasmodium falciparum/efeitos dos fármacos , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacos
17.
ACS Omega ; 3(8): 9424-9430, 2018 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31459076

RESUMO

We describe herein the design and synthesis of N-phenyl phthalimide derivatives with inhibitory activities against Plasmodium falciparum (sensitive and resistant strains) in the low micromolar range and noticeable selectivity indices against human cells. The best inhibitor, 4-amino-2-(4-methoxyphenyl)isoindoline-1,3-dione (10), showed a slow-acting mechanism similar to that of atovaquone. Enzymatic assay indicated that 10 inhibited P. falciparum cytochrome bc 1 complex. Molecular docking studies suggested the binding mode of the best hit to Qo site of the cytochrome bc 1 complex. Our findings suggest that 10 is a promising candidate for hit-to-lead development.

18.
An. acad. bras. ciênc ; 90(1,supl.1): 645-661, 2018. graf
Artigo em Inglês | LILACS | ID: biblio-886933

RESUMO

ABSTRACT Scientific and technological breakthroughs have compelled the current players in drug discovery to increasingly incorporate knowledge-based approaches. This evolving paradigm, which has its roots attached to the recent advances in medicinal chemistry, molecular and structural biology, has unprecedentedly demanded the development of up-to-date computational approaches, such as bio- and chemo-informatics. These tools have been pivotal to catalyzing the ever-increasing amount of data generated by the molecular sciences, and to converting the data into insightful guidelines for use in the research pipeline. As a result, ligand- and structure-based drug design have emerged as key pathways to address the pharmaceutical industry's striking demands for innovation. These approaches depend on a keen integration of experimental and molecular modeling methods to surmount the main challenges faced by drug candidates - in vivo efficacy, pharmacodynamics, metabolism, pharmacokinetics and safety. To that end, the Laboratório de Química Medicinal e Computacional (LQMC) of the Universidade de São Paulo has developed forefront research on highly prevalent and life-threatening neglected tropical diseases and cancer. By taking part in global initiatives for pharmaceutical innovation, the laboratory has contributed to the advance of these critical therapeutic areas through the use of cutting-edge strategies in medicinal chemistry.


Assuntos
Humanos , Tripanossomicidas/química , Química Farmacêutica , Descoberta de Drogas/métodos , Doenças Negligenciadas/tratamento farmacológico , Neoplasias/tratamento farmacológico , Antineoplásicos/química , Esquistossomose/tratamento farmacológico , Medicina Tropical/tendências , Doença de Chagas/tratamento farmacológico
19.
Future Med Chem ; 9(7): 641-657, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28509592

RESUMO

AIM: Chagas disease is endemic in Latin America and no effective treatment is available. Efforts in drug research have focused on several enzymes from Trypanosoma cruzi, among which cruzain is a validated pharmacological target. METHODOLOGY: Chemometric analyses were performed on the data set using the hologram quantitative structure-activity relationship, comparative molecular field analysis and comparative molecular similarity index analysis methods. Docking simulations were executed using the crystallographic structure of cruzain in complex with a benzimidazole inhibitor. The top-scoring enzyme-inhibitor complexes were selected for the development of the 3D quantitative structure-activity relationship (QSAR) models and to assess the inhibitor binding modes and intermolecular interactions. RESULTS: Benzimidazole derivatives as cruzain inhibitors were used in molecular docking and QSAR studies. Significant statistical indicators were obtained, and the best models demonstrated high predictive ability for an external test set (r 2pred = 0.65, 0.94 and 0.82 for hologram QSAR, comparative molecular field analysis and comparative molecular similarity index analysis, respectively). Additionally, the graphical information of the chemometric analyses demonstrated substantial complementarity with the enzyme-binding site. CONCLUSION: These results demonstrate the relevance of the QSAR models to guide the design of structurally related benzimidazole derivatives with improved potency.


Assuntos
Benzimidazóis/farmacologia , Doença de Chagas/tratamento farmacológico , Inibidores de Cisteína Proteinase/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Benzimidazóis/síntese química , Benzimidazóis/química , Benzimidazóis/metabolismo , Sítios de Ligação , Doença de Chagas/metabolismo , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/síntese química , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/metabolismo , Descoberta de Drogas , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Estrutura Molecular , Ligação Proteica , Proteínas de Protozoários/metabolismo , Relação Quantitativa Estrutura-Atividade , América do Sul , Tripanossomicidas/síntese química , Tripanossomicidas/química , Tripanossomicidas/metabolismo , Trypanosoma cruzi/metabolismo
20.
Planta Med ; 83(11): 912-920, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28264205

RESUMO

This is a comparative study on the intraspecific chemical variability of Aristolochia cordigera species, collected in two different regions of Brazil, Biome Cerrado (semiarid) and Biome Amazônia (coastal). The use of GC-MS and statistical methods led to the identification of 56 compounds. A higher percentage of palmitone and germacrene-D in the hexanes extracts of the leaves of plants from these respective biomes was observed. Phytochemical studies on the extracts led to the isolation and identification of 19 known compounds, including lignans, neolignans, aristolochic acids, indole-ß-carboline, and indole alkaloids. In addition, two new indole alkaloids, 3,4-dihydro-hyrtiosulawesine and 6-O-(ß-glucopyranosyl)hyrtiosulawesine, were isolated and a new neolignan, cis-eupomatenoid-7, was obtained in a mixture with its known isomer eupomatenoid-7. Their structures were determined by spectroscopic methods, mainly by 1D- and 2D-NMR. The occurrence of indole alkaloids is being described for the first time in the Aristolochiaceae family. Moreover, the in vitro susceptibility of intracellular amastigote and promastigote forms of Leishmania amazonensis to the alkaloids and eupomatenoid-7 were evaluated. This neolignan exhibited low activity against promastigotes (IC50 = 46 µM), while the alkaloids did not show inhibitory activity. The new alkaloid 6-O-(ß-glucopyranosyl)hyrtiosulawesine exhibited activity in the low micromolar range against Plasmodium falciparum, with an IC50 value of 5 µM and a selectivity index higher than 50.


Assuntos
Antiprotozoários/farmacologia , Aristolochia/química , Citotoxinas/farmacologia , Alcaloides Indólicos/farmacologia , Lignanas/farmacologia , Extratos Vegetais/farmacologia , Antiprotozoários/química , Antiprotozoários/isolamento & purificação , Brasil , Linhagem Celular Tumoral , Citotoxinas/química , Citotoxinas/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Alcaloides Indólicos/química , Alcaloides Indólicos/isolamento & purificação , Leishmania/efeitos dos fármacos , Lignanas/química , Lignanas/isolamento & purificação , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Plasmodium falciparum/efeitos dos fármacos
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