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1.
J Org Chem ; 86(19): 13465-13474, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34499494

RESUMO

A comprehensive study of the reaction scope of methyl 1,2,3-triazine-5-carboxylate (3a) with alkyl and aryl amidines is disclosed, reacting at room temperature at remarkable rates (<5 min, 0.1 M in CH3CN) nearly 10000-fold faster than that of unsubstituted 1,2,3-triazine and providing the product pyrimidines in high yields. C4 Methyl substitution of the 1,2,3-triazine (3b) had little effect on the rate of the reaction, whereas C4/C6 dimethyl substitution (3c) slowed the room-temperature reaction (<24 h, 0.25 M) but displayed an unaltered scope, providing the product pyrimidines in similarly high yields. Measured second-order rate constants of the reaction of 3a-c, the corresponding nitriles 3e and 3f, and 1,2,3-triazine itself (3d) with benzamidine and substituted derivatives quantitated the remarkable reactivity of 3a and 3e, verified the inverse electron demand nature of the reaction (Hammett ρ = -1.50 for substituted amidines, ρ = +7.9 for 5-substituted 1,2,3-triazine), and provided a quantitative measure of the impact of 4-methyl and 4,6-dimethyl substitution on the reactivity of the methyl 1,2,3-triazine-5-carboxylate and 5-cyano-1,2,3-triazine core heterocycles.


Assuntos
Amidinas , Triazinas , Ácidos Carboxílicos , Elétrons , Pirimidinas
2.
J Org Chem ; 86(19): 13734-13743, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34541847

RESUMO

An efficient, facile, and eco-friendly synthesis of pyrimidine derivatives has been developed. It involves a [3 + 2 + 1] three-component annulation of amidines, ketones, and one carbon source. N,N-Dimethylaminoethanol is oxidized through C(sp3)-H activation to provide the carbon donor. One C-C and two C-N bonds are formed during the oxidative annulation process. The reaction shows good tolerance to many important functional groups in air, making this methodology a highly versatile alternative, and significant improvement to the existing methods for structuring a pyrimidine framework, especially 4-aliphatic pyrimidines.


Assuntos
Amidinas , Cetonas , Carbono , Catálise , Deanol , Pirimidinas
4.
Molecules ; 26(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34361571

RESUMO

Inducible nitric oxide synthase (iNOS) is a crucial enzyme involved in monocyte cell response towards inflammation, and it is responsible for the production of sustained amounts of nitric oxide. This free radical molecule is involved in the defense against pathogens; nevertheless, its continuous and dysregulated production contributes to the development of several pathological conditions, including inflammatory and autoimmune diseases. In the present study, we investigated the effects of two new iNOS inhibitors, i.e., 4-(ethanimidoylamino)-N-(4-fluorophenyl)benzamide hydrobromide (FAB1020) and N-{3-[(ethanimidoylamino)methyl]benzyl}-l-prolinamidedihydrochloride (CM554), on human LPS-stimulated monocytes, using the 1400 W compound as a comparison. Our results show that CM544 and FAB1020 are selective and decrease cytotoxicity, IL-6 secretion and LPS-stimulated monocyte migration. Furthermore, the modulation of iNOS, nitrotyrosine and Nrf2 were analyzed at the protein level. Based on the collected preliminary results, the promising therapeutic value of the investigated compounds emerges, as they appear able to modulate the pro-inflammatory LPS-stimulated response in the low micromolar range in human monocytes.


Assuntos
Amidinas/farmacologia , Inibidores Enzimáticos/farmacologia , Lipopolissacarídeos/toxicidade , Monócitos/enzimologia , Óxido Nítrico Sintase Tipo II , Prolina/análogos & derivados , Humanos , Interleucina-6/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/metabolismo , Prolina/farmacologia
5.
J Enzyme Inhib Med Chem ; 36(1): 1952-1967, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34455887

RESUMO

A series of 6-amidinobenzothiazoles, linked via phenoxymethylene or directly to the 1,2,3-triazole ring with a p-substituted phenyl or benzyl moiety, were synthesised and evaluated in vitro against four human tumour cell lines and the protozoan parasite Trypanosoma brucei. The influence of the type of amidino substituent and phenoxymethylene linker on antiproliferative and antitrypanosomal activities was observed, showing that the imidazoline moiety had a major impact on both activities. Benzothiazole imidazoline 14a, which was directly connected to N-1-phenyl-1,2,3-triazole, had the most potent growth-inhibitory effect (IC50 = 0.25 µM) on colorectal adenocarcinoma (SW620), while benzothiazole imidazoline 11b, containing a phenoxymethylene linker, exhibited the best antitrypanosomal potency (IC90 = 0.12 µM). DNA binding assays showed a non-covalent interaction of 6-amidinobenzothiazole ligands, indicating both minor groove binding and intercalation modes of DNA interaction. Our findings encourage further development of novel structurally related 6-amidino-2-arylbenzothiazoles to obtain more selective anticancer and anti-HAT agents.


Assuntos
Antiprotozoários/síntese química , Benzotiazóis/síntese química , Substâncias Intercalantes/síntese química , Trypanosoma brucei brucei/efeitos dos fármacos , Amidinas/química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Antiprotozoários/farmacologia , Benzotiazóis/farmacologia , Proliferação de Células/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , DNA/química , Avaliação Pré-Clínica de Medicamentos , Humanos , Imidazolinas/química , Substâncias Intercalantes/farmacologia , Conformação de Ácido Nucleico , Relação Estrutura-Atividade , Triazóis/química
6.
Ultrason Sonochem ; 77: 105685, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34364069

RESUMO

Protein oxidation leads to covalent modification of structure and deterioration of functional properties of quinoa protein. The objective of this study was to investigate the effects of ultrasonic treatment on the functional and physicochemical properties of quinoa protein oxidation aggregates. In this concern, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) was selected as oxidative modification of quinoa protein. The microstructure of quinoa protein displayed by scanning electron microscope (SEM) indicated that oxidation induced extensive aggregation, leading to carbonylation and degradation of sulfhydryl groups. Aggregation induced by oxidation had a negative effect on the solubility, turbidity, emulsifying stability. However, according to the analysis of physicochemical properties, ultrasonic significantly improved the water solubility of quinoa protein. The quinoa protein treated by ultrasonic for 30 min exhibited the best dispersion stability in water, which corresponded to the highest ζ-potential, smallest particle size and most uniform distribution. Based on the FT-IR, SDS-PAGE and surface hydrophobicity analysis, the increase of α-helix, ß-turn and surface hydrophobicity caused by cavitation effect appeared to be the main mechanism of quinoa protein solubilization. In addition, the hydrophobic region of the protein was re-buried by excessive ultrasonic treatment, and the protein molecules were reaggregated by disulfide bonds. Microstructural observations further confirmed that ultrasonic treatment effectively inhibited protein aggregation and improved the functional properties of quinoa protein.


Assuntos
Chenopodium quinoa/química , Proteínas de Plantas/química , Agregados Proteicos , Ondas Ultrassônicas , Amidinas/química , Qualidade dos Alimentos , Oxirredução
7.
ACS Chem Biol ; 16(8): 1365-1376, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34328300

RESUMO

G-quadruplex (G4) DNA structures are widespread in the human genome and are implicated in biologically important processes such as telomere maintenance, gene regulation, and DNA replication. Guanine-rich sequences with potential to form G4 structures are prevalent in the promoter regions of oncogenes, and G4 sites are now considered as attractive targets for anticancer therapies. However, there are very few reports of small "druglike" optical G4 reporters that are easily accessible through one-step synthesis and that are capable of discriminating between different G4 topologies. Here, we present a small water-soluble light-up fluorescent probe that features a minimalistic amidinocoumarin-based molecular scaffold that selectively targets parallel G4 structures over antiparallel and non-G4 structures. We showed that this biocompatible ligand is able to selectively stabilize the G4 template resulting in slower DNA synthesis. By tracking individual DNA molecules, we demonstrated that the G4-stabilizing ligand perturbs DNA replication in cancer cells, resulting in decreased cell viability. Moreover, the fast-cellular entry of the probe enabled detection of nucleolar G4 structures in living cells. Finally, insights gained from the structure-activity relationships of the probe suggest the basis for the recognition of parallel G4s, opening up new avenues for the design of new biocompatible G4-specific small molecules for G4-driven theranostic applications.


Assuntos
Amidinas/química , Cumarínicos/química , DNA/análise , Corantes Fluorescentes/química , Quadruplex G , Amidinas/síntese química , Amidinas/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Cumarínicos/síntese química , Cumarínicos/metabolismo , DNA/genética , DNA/metabolismo , Replicação do DNA/efeitos dos fármacos , Desenho de Fármacos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/metabolismo , Células HeLa , Humanos , Limite de Detecção , Microscopia Confocal , Microscopia de Fluorescência , Estrutura Molecular , Relação Estrutura-Atividade
8.
Chirurg ; 92(9): 809-821, 2021 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-34255114

RESUMO

Endoscopic management of umbilical and incisional hernias has adapted to the limitations of conventional laparoscopic instruments over the past 30 years. This includes the development of meshes for intraperitoneal placement (intraperitoneal onlay mesh, IPOM), with antiadhesive coatings; however, adhesions do occur in a significant proportion of these patients. Minimally invasive procedures result in fewer perioperative complications, but with a slightly higher recurrence rate. With the ergonomic resources of robotics, which offers angled instruments, it is now possible to implant meshes in a minimally invasively manner in different abdominal wall layers while achieving morphologic and functional reconstruction of the abdominal wall. This video article presents the treatment of ventral and incisional hernias with mesh implantation into the preperitoneal space (robot-assisted transabdominal preperitoneal ventral hernia repair, r­ventral TAPP) as well as into the retrorectus space (r-Rives and robotic transabdominal retromuscular umbilical prosthetic repair, r­TARUP, respectively). The results of a cohort study of 118 consecutive patients are presented and discussed with regard to the added value of the robotic technique in extraperitoneal mesh implantation and in the training of residents.


Assuntos
Hérnia Ventral , Hérnia Incisional , Laparoscopia , Robótica , Amidinas , Estudos de Coortes , Hérnia Ventral/cirurgia , Herniorrafia , Humanos , Hérnia Incisional/cirurgia , Telas Cirúrgicas
9.
J Agric Food Chem ; 69(28): 7960-7968, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34240860

RESUMO

One crucial aspect of the Maillard reaction is the formation of reactive α-dicarbonyl structures like glyoxal, which are prone toward further reactions with proteins, e.g., the N6-amino group of lysine. The initially formed labile glyoxal-imine was previously established as a key intermediate in the formation of the advanced glycation end products N6-carboxymethyl lysine (CML), glyoxal lysine amide (GOLA), glyoxal lysine dimer (GOLD), and N6-glycolyl lysine (GALA). Here, we introduce a novel amidine cross-link structure N1,N2-bis-(5-amino-5-carboxypentyl)-2-hydroxy-acetamidine (glyoxal lysine amidine, GLA), which is formed exclusively from glyoxal through the same isomerization cascade. After independent synthesis of the authentic reference standard, we were able to quantitate this cross-link in incubations of 40 mM N2-t-Boc-lysine with glyoxal and various sugars (40-100 mM) under mild conditions (pH 7.4, 37 °C) using an HPLC-MS/MS method. Furthermore, incubations of proteins (6 mg/mL) with 50 mM glyoxal confirmed the cross-linking by GLA, which was additionally identified in acidic hydrolyzed proteins of butter biscuits after HPLC enrichment.


Assuntos
Glioxal , Lisina , Amidinas , Produtos Finais de Glicação Avançada , Reação de Maillard , Espectrometria de Massas em Tandem
11.
Eur J Med Chem ; 222: 113625, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34146914

RESUMO

Dicationic diamidines have been well established as potent antiparasitic agents with proven activity against tropical diseases like trypanosomiasis and malaria. This work presents the synthesis of new mono and diflexible triaryl amidines (6a-c, 13a,b and 17), their aza analogues (23 and 27) and respective methoxyamidine prodrugs (5, 7, 12a,b, 22 and 26). All diamidines were assessed in vitro against Trypanosoma brucei rhodesiense (T. b. r.) and Plasmodium falciparum (P. f.) where they displayed potent to moderate activities at the nanomolar level with IC50s = 11-378 nM for T. b. r. and 4-323 nM against P. f.. In vivo efficacy testing against T. b. r. STIB900 has shown the monoflexible diamidine 6c as the most potent derivative in this study eliciting 4/4 cures of infected mice for a treatment period of >60 days upon a 4 × 5 mg/kg dose i. p. treatment. Moreover, thermal melting analysis measurement ΔTm for this series of diamidines/poly (dA-dT) complexes fell between 0.5 and 19 °C with 6c showing the highest binding to the DNA minor groove. Finally, a 50 ns molecular dynamics study of an AT-rich DNA dodecamer with compound 6c revealed a strong binding complex supported by vdW and electrostatic interactions.


Assuntos
Amidinas/farmacologia , Antiparasitários/farmacologia , Compostos Aza/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Pró-Fármacos/farmacologia , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Amidinas/síntese química , Amidinas/química , Antiparasitários/síntese química , Antiparasitários/química , Compostos Aza/síntese química , Compostos Aza/química , Relação Dose-Resposta a Droga , Modelos Moleculares , Estrutura Molecular , Testes de Sensibilidade Parasitária , Pró-Fármacos/síntese química , Pró-Fármacos/química , Relação Estrutura-Atividade , Trypanosoma brucei rhodesiense/enzimologia
12.
Biochem Biophys Res Commun ; 565: 64-71, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34098313

RESUMO

Neutrophil extracellular traps (NETs) are extracellular webs of DNA, histones and granular contents that are released by neutrophils to control infections. However, NETs that is not properly regulated can propagate inflammation and thrombosis. It was recognized that viruses can induce NETs. As a synthetic analog of viral double-stranded (ds) RNA, polyinosinic-polycytidylic acid [poly(I:C)] is known to induce inflammation and thrombosis. However, whether and how poly(I:C) modulates NETs remains unclear. Here, we have demonstrated that poly(I:C) induced extracellular DNA traps in human neutrophils in a dose-dependent manner. Further, poly(I:C) or dsRNA virus elevated the levels of myeloperoxidase-DNA complexes and citrullinated histone H3, which are specific markers of NETs, in both neutrophil supernatants and mouse plasma. Interestingly, a potent peptidylarginine deiminase 4 (PAD4) inhibitor, BB-CL-Amidine (BB-CLA) or PAD4 knockdown effectively prevented poly(I:C)-induced NETs formation and release. In addition, BB-CLA abrogated poly(I:C)-triggered neutrophil activation and infiltration, and vascular permeability in lungs. BB-CLA also attenuated poly(I:C)-induced thrombocytopenia in circulation, fibrin deposition and thrombus formation in tissues. Taken together, these results suggest that viral mimetic poly(I:C) may induce NETs-dependent inflammation and thrombosis through PAD4, and that inhibiting PAD4 may become a good strategy to protect against viral infection-caused inflammation/thrombosis-related pathological conditions of diseases.


Assuntos
Armadilhas Extracelulares/efeitos dos fármacos , Inflamação/metabolismo , Neutrófilos/efeitos dos fármacos , Poli I-C/farmacologia , Proteína-Arginina Desiminase do Tipo 4/metabolismo , Trombose/metabolismo , Amidinas/farmacologia , Animais , Células Cultivadas , Chlorocebus aethiops , Humanos , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ativação de Neutrófilo/efeitos dos fármacos , Neutrófilos/metabolismo , Proteína-Arginina Desiminase do Tipo 4/antagonistas & inibidores , Trombose/patologia
13.
Chirurg ; 92(8): 707-720, 2021 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-34061241

RESUMO

The treatment of inguinal hernias with open and minimally invasive procedures has reached a high standard in terms of outcome over the past 30 years. However, there is still need for further improvement, mainly in terms of reduction of postoperative seroma, chronic pain, and recurrence. This video article presents the endoscopic anatomy of the groin with regard to robotic transabdominal preperitoneal patch plasty (r­TAPP) and illustrates the surgical steps of r­TAPP with respective video sequences. The results of a cohort study of 302 consecutive hernias operated by r­TAPP are presented and discussed in light of the added value of the robotic technique, including advantages for surgical training. r­TAPP is the natural evolution of conventional TAPP and has the potential to become a new standard as equipment availability increases and material costs decrease. Future studies will also have to refine the multifaceted added value of r­TAPP with new parameters.


Assuntos
Hérnia Inguinal , Laparoscopia , Procedimentos Cirúrgicos Robóticos , Amidinas , Estudos de Coortes , Hérnia Inguinal/cirurgia , Herniorrafia , Humanos , Telas Cirúrgicas , Resultado do Tratamento
15.
Mol Carcinog ; 60(6): 413-426, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33866606

RESUMO

Ours and other previous studies have shown that CYP4Z1 is specifically and highly expressed in breast cancer, and acts as a promoter for the stemness of breast cancer cells. Here, we explored whether targeting CYP4Z1 could attenuate the stemness of breast cancer cells using HET0016, which has been confirmed to be an inhibitor of CYP4Z1 by us and others. Using the transcriptome-sequencing analysis, we found that HET0016 suppressed the expression of cancer stem cell (CSC) markers and stem cell functions. Additionally, HET0016 indeed reduced the stemness of breast cancer cells, as evident by the decrease of stemness marker expression, CD44+ /CD24- subpopulation with stemness, mammary-spheroid formation, and tumor-initiating ability. Moreover, HET0016 suppressed the metastatic capability through in vitro and in vivo experiments. Furthermore, we confirmed that HET0016 suppressed CYP4Z1 activity, and HET0016-induced inhibition on the stemness and metastasis of breast cancer cells was rescued by CYP4Z1 overexpression. Thus, our results demonstrate that HET0016 can attenuate the stemness of breast cancer cells through targeting CYP4Z1.


Assuntos
Amidinas/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Família 4 do Citocromo P450/genética , Células-Tronco Neoplásicas/efeitos dos fármacos , Amidinas/administração & dosagem , Animais , Antinematódeos/administração & dosagem , Antinematódeos/farmacologia , Linhagem Celular Tumoral , Família 4 do Citocromo P450/antagonistas & inibidores , Relação Dose-Resposta a Droga , Feminino , Humanos , Camundongos Endogâmicos BALB C , Células-Tronco Neoplásicas/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Int J Mol Sci ; 22(8)2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33921206

RESUMO

Oxidation is an important degradation pathway of protein drugs. The susceptibility to oxidation is a common concern for therapeutic proteins as it may impact product efficacy and patient safety. In this work, we used 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) as an oxidative stress reagent to evaluate the oxidation of therapeutic antibodies. In addition to the oxidation of methionine (Met) and tryptophan (Trp) residues, we also observed an increase of protein aggregation. Size-exclusion chromatography and multi-angle light scattering showed that the soluble aggregates induced by AAPH consist of dimer, tetramer, and higher-order aggregate species. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that inter-molecular disulfide bonds contributed to the protein aggregation. Furthermore, intrinsic fluorescence spectra suggested that dimerization of tyrosine (Tyr) residues could account for the non-reducible cross-links. An excipient screening study demonstrated that Trp, pyridoxine, or Tyr could effectively reduce protein aggregation due to oxidative stress. This work provides valuable insight into the mechanisms of oxidative-stress induced protein aggregation, as well as strategies to minimize such aggregate formation during the development and storage of therapeutic proteins.


Assuntos
Anticorpos Monoclonais/química , Estresse Oxidativo/genética , Proteínas/química , Proteólise/efeitos dos fármacos , Amidinas , Anticorpos Monoclonais/genética , Dimerização , Radicais Livres/química , Radicais Livres/metabolismo , Humanos , Oxidantes/química , Oxidantes/farmacologia , Oxirredução/efeitos dos fármacos , Agregados Proteicos/genética , Proteínas/genética , Proteínas/uso terapêutico , Triptofano/química , Triptofano/genética
17.
Org Lett ; 23(7): 2643-2647, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33749284

RESUMO

A method for the enantio- and chemoselective iridium-catalyzed O-allylation of oximes is described. Kinetic resolution in an intramolecular setting provides enantioenriched oxime ethers and aliphatic allylic alcohols. The synthetic potential of the products generated with this method is showcased by their elaboration into a series of heterocyclic compounds and the formal synthesis of glycoprotein GP IIb-IIIa receptor antagonist (-)-roxifiban. Preliminary mechanistic experiments and computational data shed light on the remarkable chemoselectivity of the reaction.


Assuntos
Amidinas/química , Irídio/química , Isoxazóis/química , Oximas/química , Propanóis/química , Catálise , Estrutura Molecular , Estereoisomerismo
18.
Org Biomol Chem ; 19(12): 2784-2793, 2021 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-33704342

RESUMO

Unlike the closely related and widely investigated amidino-substituted benzimidazoles and benzothiazoles with a range of demonstrated biological activities, the matching benzoxazole analogues still remain a largely understudied and not systematically evaluated class of compounds. To address this challenge, we utilized the Pinner reaction to convert isomeric cyano-substituted 2-aminophenols into their amidine derivatives, which were isolated as hydrochlorides and/or zwitterions, and whose structure was confirmed by single crystal X-ray diffraction. The key step during the Pinner synthesis of the crucial carboximidate intermediates was characterized through mechanistic DFT calculations, with the obtained kinetic and thermodynamic parameters indicating full agreement with the experimental observations. The obtained amidines were subjected to a condensation reaction with aryl carboxylic acids that allowed the synthesis of a new library of 5- and 6-amidino substituted 2-arylbenzoxazoles. Their antiproliferative features against four human tumour cell lines (SW620, HepG2, CFPAC-1, HeLa) revealed sub-micromolar activities on SW620 for several cyclic amidino 2-naphthyl benzoxazoles, thus demonstrating the usefulness of the proposed synthetic strategy and promoting amidino substituted 2-aminophenols as important building blocks towards biologically active systems.


Assuntos
Amidinas/farmacologia , Aminofenóis/farmacologia , Antineoplásicos/farmacologia , Benzoxazóis/farmacologia , Amidinas/química , Aminofenóis/química , Antineoplásicos/síntese química , Antineoplásicos/química , Benzoxazóis/síntese química , Benzoxazóis/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Teoria da Densidade Funcional , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular
19.
J Med Chem ; 64(6): 3035-3047, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33666415

RESUMO

3-Hydroxypropanamidines are a new promising class of highly active antiplasmodial agents. The most active compound 22 exhibited excellent antiplasmodial in vitro activity with nanomolar inhibition of chloroquine-sensitive and multidrug-resistant parasite strains ofPlasmodium falciparum (with IC50 values of 5 and 12 nM against 3D7 and Dd2 strains, respectively) as well as low cytotoxicity in human cells. In addition, 22 showed strong in vivo activity in thePlasmodium berghei mouse model with a cure rate of 66% at 50 mg/kg and a cure rate of 33% at 30 mg/kg in the Peters test after once daily oral administration for 4 consecutive days. A quick onset of action was indicated by the fast drug absorption shown in mice. The new lead compound was also characterized by a high barrier to resistance and inhibited the heme detoxification machinery in P. falciparum.


Assuntos
Amidinas/química , Amidinas/farmacologia , Antimaláricos/química , Antimaláricos/farmacologia , Malária Falciparum/tratamento farmacológico , Plasmodium falciparum/efeitos dos fármacos , Amidinas/farmacocinética , Amidinas/uso terapêutico , Animais , Antimaláricos/farmacocinética , Antimaláricos/uso terapêutico , Linhagem Celular , Desenho de Fármacos , Humanos , Malária/tratamento farmacológico , Camundongos , Testes de Sensibilidade Parasitária , Plasmodium berghei/efeitos dos fármacos , Propano/química , Propano/farmacocinética , Propano/farmacologia , Propano/uso terapêutico
20.
Free Radic Biol Med ; 167: 258-270, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-33731307

RESUMO

The present work examined the oxidation and crosslinking of the anti-bacterial enzyme lysozyme (Lyso), which is present in multiple biological fluids, and released from the cytoplasmic granules of macrophages and neutrophils at sites of infection and inflammation. It is therefore widely exposed to oxidants including peroxyl radicals (ROO•). We hypothesized that exposure to ROO• would generate specific modifications and inter- and intra-protein crosslinks via radical-radical reactions. Lyso was incubated with AAPH (2,2'-azobis(2-methylpropionamidine) dihydrochloride) as a ROO• source. Enzymatic activity was assessed, while oxidative modifications were detected and quantified using electrophoresis and liquid chromatography (UPLC) with fluorescence or mass detection (MS). Computational models of AAPH-Lyso interactions were developed. Exposure of Lyso to AAPH (10 and 100 mM for 3 h, and 20 mM for 1 h), at 37 °C, decreased enzymatic activity. 20 mM AAPH showed the highest efficiency of Lyso inactivation (1.78 mol of Lyso inactivated per ROO•). Conversion of Met to its sulfoxide, and to a lesser extent, Tyr oxidation to 3,4-dihydroxyphenylalanine and diTyr, were detected by UPLC-MS. Extensive transformation of Trp, involving short chain reactions, to kynurenine, oxindole, hydroxytryptophan, hydroperoxides or di-alcohols, and N-formyl-kynurenine was detected, with Trp62, Trp63 and Trp108 the most affected residues. Interactions of AAPH inside the negatively-charged catalytic pocket of Lyso, with Trp108, Asp52, and Glu35, suggest that Trp108 oxidation mediates, at least partly, Lyso inactivation. Crosslinks between Tyr20-Tyr23 (intra-molecular), and Trp62-Tyr23 (inter-molecular), were detected with both proximity (Tyr20-Tyr23), and chain flexibility (Trp62) appearing to favor the formation of covalent crosslinks.


Assuntos
Muramidase , Tirosina , Amidinas , Cromatografia Líquida , Radicais Livres , Muramidase/metabolismo , Oxirredução , Peróxidos , Espectrometria de Massas em Tandem
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