RESUMO
The aim of the present study was investigate the binding affinity of 5-((4-methoxyphenyl)thio)benzo[c][1,2,5]thiadiazole (MTDZ) with acetylcholinesterase (AChE). We also evaluated the effect of MTDZ against scopolamine (SCO)-induced amnesia in mice and we looked at the toxicological potential of this compound in mice. The binding affinity of MTDZ with AChE was investigated by molecular docking analyses. For an experimental model, male Swiss mice were treated daily with MTDZ (10 mg/kg, intragastrically (i.g.)) or canola oil (10 ml/kg, i.g.), and induced, 30 min later, with injection of SCO (0.4 mg/kg, intraperitoneally (i.p.)) or saline (0.9%, 5 ml/kg, i.p.) daily. From day 1 to day 10, mice were submitted to the behavioral tasks (Barnes maze, open-field, object recognition and location, Y-maze and step-down inhibitory avoidance tasks), 30 min after induction with SCO. On the tenth day, the animals were euthanized and blood was collected for the analysis of biochemical markers (creatinine, aspartate (AST), and alanine (ALT) aminotransferase). MTDZ interacts with residues of the AChE active site. SCO caused amnesia in mice by changing behavioral tasks. MTDZ treatment attenuated the behavioral changes caused by SCO. In ex vivo assay, MTDZ also protected against the alteration of AChE activity, reactive species (RS) levels, thiobarbituric acid reative species (TBARS) levels, catalase (CAT) activity in tissues, as well as in transaminase activities of plasma caused by SCO in mice. In conclusion, MTDZ presented anti-amnesic action through modulation of the cholinergic system and provided protection from kidney and liver damage caused by SCO.
Assuntos
Acetilcolinesterase/metabolismo , Amnésia/tratamento farmacológico , Inibidores da Colinesterase/uso terapêutico , Nootrópicos/uso terapêutico , Sulfetos/uso terapêutico , Tiadiazóis/uso terapêutico , Amnésia/induzido quimicamente , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Inibidores da Colinesterase/metabolismo , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Camundongos , Simulação de Acoplamento Molecular , Nootrópicos/metabolismo , Ligação Proteica , Escopolamina , Sulfetos/metabolismo , Tiadiazóis/metabolismoRESUMO
Trypanosoma cruzi (T. cruzi) triosephosphate isomerase (TcTIM) is a glycolytic enzyme essential for parasite survival and has been considered an interesting target for the development of new antichagasic compounds. The homodimeric enzyme is catalytically active only as a dimer. Interestingly, significant differences exist between the human and parasite TIMs interfaces with a sequence identity of 52%. Therefore, compounds able to specifically disrupt TcTIM but not Homo sapiens TIM (hTIM) dimer interface could become selective antichagasic drugs. In the present work, the binding modes of 1,2,4-thiadiazol, phenazine and 1,2,6-thiadiazine derivatives to TcTIM were investigated using molecular docking combined with molecular dynamics (MD) simulations. The results show that phenazine and 1,2,6-thiadiazine derivatives, 2 and 3, act as dimer-disrupting inhibitors of TcTIM having also allosteric effects in the conformation of the active site. On the other hand, the 1,2,4-thiadiazol derivative 1 binds into the active site causing a significant decrease in enzyme mobility in both monomers. The loss of conformational flexibility upon compound 1 binding suggests that this inhibitor could be preventing essential motions of the enzyme required for optimal activity. The lack of inhibitory activity of 1 against hTIM was also investigated and seems to be related with the high mobility of hTIM which would hinder the formation of a stable ligand-enzyme complex. This work has contributed to understand the mechanism of action of this kind of inhibitors and could result of great help for future rational novel drug design.
Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Triose-Fosfato Isomerase/antagonistas & inibidores , Trypanosoma cruzi/enzimologia , Domínio Catalítico , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Fenazinas/química , Fenazinas/metabolismo , Tiadiazinas/química , Tiadiazinas/metabolismo , Tiadiazóis/química , Tiadiazóis/metabolismo , Triose-Fosfato Isomerase/química , Triose-Fosfato Isomerase/metabolismoRESUMO
Megazol (7) is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8) in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR) enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7) for nitrogen (in the triazole in 8), the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.
Assuntos
Animais , Humanos , Masculino , Camundongos , Nitrorredutases/efeitos dos fármacos , Tiadiazóis , Triazóis , Tripanossomicidas , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/enzimologia , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Nitrorredutases/metabolismo , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tiadiazóis/química , Tiadiazóis/metabolismo , Tiadiazóis/farmacologia , Tiadiazóis/toxicidade , Triazóis/química , Triazóis/metabolismo , Triazóis/farmacologia , Triazóis/toxicidade , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacosRESUMO
Megazol (7) is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8) in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR) enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7) for nitrogen (in the triazole in 8), the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.
Assuntos
Nitrorredutases/efeitos dos fármacos , Tiadiazóis , Triazóis , Tripanossomicidas , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/enzimologia , Animais , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos , Masculino , Camundongos , Nitrorredutases/metabolismo , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tiadiazóis/química , Tiadiazóis/metabolismo , Tiadiazóis/farmacologia , Tiadiazóis/toxicidade , Triazóis/química , Triazóis/metabolismo , Triazóis/farmacologia , Triazóis/toxicidade , Tripanossomicidas/química , Tripanossomicidas/farmacologia , Tripanossomicidas/toxicidade , Trypanosoma cruzi/efeitos dos fármacosRESUMO
4-hydroxy-3-methoxybenzaldehyde was used as starting material to obtain a number of 1, 3, 4-thiadiazole alkylamide derivatives. The pharmacological properties of these conformationally restricted capsaicin analogues were evaluated on HEK-293T cells transiently expressing TRPV1 receptor. By means of a highthroughput calcium imaging assay we find that 1, 3, 4-thiadiazoles (compounds 8-15) act as potent antagonists of the capsaicin receptor, inhibiting both, the capsaicin- and temperature-dependent activation. Docking studies suggested a different binding orientation on the vanilloid binding site when compared with capsaicin analogues, such as 5-iodononivamide. Overall, our studies suggest that 1, 3, 4-thiadiazoles interact with capsaicin's binding region of the receptor, although using a different set of interactions within the vanilloid binding pocket.
Assuntos
Capsaicina/análogos & derivados , Desenho de Fármacos , Canais de Cátion TRPV/antagonistas & inibidores , Tiadiazóis/síntese química , Tiadiazóis/farmacologia , Animais , Técnicas de Química Sintética , Células HEK293 , Humanos , Simulação de Acoplamento Molecular , Conformação Proteica , Ratos , Eletricidade Estática , Relação Estrutura-Atividade , Canais de Cátion TRPV/química , Canais de Cátion TRPV/metabolismo , Tiadiazóis/química , Tiadiazóis/metabolismoRESUMO
The mesoionic derivative 4-phenyl-5-[4-nitrocinnamoyl]-1,3,4-thiadiazolyl-2-phenylamine chloride (MI-D) has antitumoral and anti-inflammatory effects. In this study, we present aspects of its metabolism and toxicity in mice. MI-D was metabolized in vitro by liver microsome, generating a main product with a much shorter retention time than MI-D in high-performance liquid chromatography (HPLC) analysis but with a spectrum similar to that of the original molecule. Mass spectrometry with electrospray ionization in positive mode analysis of the purified compound by HPLC indicated that the product of metabolism has four additional hydroxyl groups (m/z = 465) compared with MI-D (m/z = 401). The HPLC analyses of plasma and urine samples from mice treated with MI-D showed the presence of the metabolite product. The kinetic parameters K(m) (19.5 +/- 4.5 microM) and V(max) [1.5 +/- 0.4 units of fluorescence/(100 microg of microsomal protein/mL/s)] were estimated, confirming the metabolism of MI-D and indicating that the reaction follows Michaelis-Menten kinetics. Acute toxicity was established on the basis of an estimation of mean lethal dose (LD-50; 181.2 mg/kg) and histopathological analysis of animals that survived the LD-50 test. Abdominal adhesions, inflammatory foci, and formation of granulomas were observed. Altogether, the results contribute to the advancement of research in support of MI-D as a future chemotherapeutic drug.
Assuntos
Cinamatos/metabolismo , Microssomos Hepáticos/metabolismo , Tiadiazóis/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Cinamatos/toxicidade , Dose Letal Mediana , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Camundongos , Tiadiazóis/toxicidadeRESUMO
Benzothiazole (BT) is a toxic and poorly biodegradable contaminant, usually found in wastewater from rubber related applications. This compound could be effectively eliminated using advanced treatment processes. This paper compares experimental results on detoxification systems based on ozone oxidation, activated carbon adsorption, and simultaneous adsorption-oxidation using ozone in the presence of activated carbon. The effect of pH (2-11), and the presence of radical scavengers (tert-butyl alcohol and sodium carbonate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1 L differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with activated carbon adsorption increases the overall BT oxidation rate with respect to the ozonation process and activated carbon adsorption. In the presence of free radical scavenger, only a 44% reduction in BT removal rate is observed in the simultaneous treatment, as compared with 72% when ozonation treatment is used, suggesting that BT oxidation reactions mainly take place on the activated carbon surface.
Assuntos
Carvão Vegetal/química , Ozônio/química , Tiadiazóis/toxicidade , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Adsorção , Biodegradação Ambiental , Carbonatos/farmacologia , Sequestradores de Radicais Livres/farmacologia , Concentração de Íons de Hidrogênio , Oxirredução , Tiadiazóis/isolamento & purificação , Tiadiazóis/metabolismo , Fatores de Tempo , terc-Butil Álcool/farmacologiaRESUMO
In this work we reported the synthesis and the trypanocidal profile of new 1,3,4-thiadiazole-2-arylhydrazone derivatives of nitroimidazole series (4) or phenyl series (5), designed by exploring the molecular hybridization approach between megazol (2) and guanyl hydrazone derivative (3). The evaluation of the activity against bloodstream trypomastigote forms of Trypanosoma cruzi forms lead us to identify a new potent trypamomicide prototype, that is, brazilizone A (4k), which present an IC50/24 h=5.3 microM.
Assuntos
Hidrazonas/síntese química , Hidrazonas/farmacologia , Tiadiazóis/química , Tiadiazóis/farmacologia , Tripanossomicidas/síntese química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Hidrazonas/química , Hidrazonas/metabolismo , Estrutura Molecular , Mutagênicos , Testes de Sensibilidade Parasitária , Relação Estrutura-Atividade , Tiadiazóis/síntese química , Tiadiazóis/metabolismo , Tripanossomicidas/química , Trypanosoma cruzi/metabolismoRESUMO
The bioreductive activation of megazol [2-amino-5(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole] promoted by ferredoxin: NADP+ oxidoreductase, rat liver microsomes and cellular fractions of Trypanosoma cruzi, Y strain, was investigated. Direct ESR detection and characterization by computer simulation of the megazol nitro anion radical were possible in the presence of NADPH and ferredoxin: NADP+ oxidoreductase under anaerobic conditions. By contrast, the megazol nitro anion radical was not detected in the presence of either rat liver microsomes or cellular fractions of T. cruzi under conditions where the corresponding nifurtimox anion radical was observed. The inefficiency of rat liver microsomes in catalyzing megazol reduction was also attested by visible light absorption spectroscopy. In the presence of cellular fractions of T. cruzi supplemented with NAD(P)H, megazol marginally affected oxygen consumption and decreased the yield of oxyradicals that can be spin-trapped with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). Our results indicate a restricted bioreductive metabolism of megazol and suggest that its trypanocidal activity is unrelated to a redox-cycling process.