RESUMEN
Schistosomiasis is an endemic disease in Brazil. It is important to broaden the treatment options to control and containment of the disease. Thiazolidine derivatives appear as important alternatives to treatment. In vitro studies have demonstrated excellent schistosomiasis activity for LPSF/GQ-238. The molecule, however, has poorly water-soluble. This study focused on increasing the aqueous solubility of LPSF/GQ-238 by obtaining solid dispersions. Were prepared by the solvent techniques, using Soluplus®, Polyethylene glycol (PEG), and Polyvinylpyrrolidone (PVP-K30) as carriers. Solubility tests, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Exploratory Differential Calorimetry (DSC), and Raman Spectroscopy characterized these new intermediate products. The solubility tests showed that the higher the proportion of polymer used in the preparation of the dispersion, the greater the solubility presented. The observation of the morphology by SEM analysis, elucidated, that the new chemical entity (NCE) has a characteristic crystalline structure. The folding of this structure by the polymer was observed in all analyzed dispersions, thus demonstrating the amorphous state of the product. The scales observed in the structures of the dispersions demonstrate the successive wrinkles that occurred. The greater the proportion of the polymer, the greater the number of folds that occurred, which may explain the greater solubility observed in these preparations. The X-ray diffraction profile of the NCE reveals the presence of intense peaks, presenting a crystalline pattern. The polymer, on the other hand, shows amorphous nature, evidenced by the absence of peaks. All the analyzed dispersions did not present the characteristic peaks of the NCE, evidencing the amorphous behavior of the products. The thermal degradation profile of the NCE presents a characteristic crystalline structure endothermic peak. This peak was not observed in any of the obtained dispersions, evidencing the obtaining of a new solid state. Raman spectroscopy showed that peaks in the range 200-400 (cm-1) by NCE were lost when compared to all analyzed dispersions, showing a slight change in the structure of the molecule when dispersed, probably due to the formation of hydrogen bonds with the polymer. The in vitro study showed a significant improvement in the activity of the NCE against the adult worm and to the schistosomulae. It was possible to observe that the obtained solid dispersions were physicochemically and biologically viable for schistosomicidal treatment due to the increase of solubility of the molecule.
Asunto(s)
Esquistosomiasis , Esquistosomicidas , Humanos , Tiazolidinas , Esquistosomicidas/farmacología , Espectroscopía Infrarroja por Transformada de Fourier , Polímeros/química , Povidona , Difracción de Rayos XRESUMEN
Abstract Oxazolidine derivatives (OxD) have been described as third-line antibiotics and antitumoral agents. The inclusion complexes based on cyclodextrin could improve the solubility and bioavailability of these compounds. A novel synthetic OxD was used, and its inclusion complexes were based on 2-hydroxy-beta-cyclodextrin (2-HPßCD). We conducted an in silico study to evaluate the interaction capacity between OxD and 2-HPßCD. Characterization studies were performed through scanning electron microscopy (SEM), Fourier-transformed infrared (FTIR), nuclear magnetic resonance spectroscopy (1H-NMR), X-ray diffraction (XRD), and thermal analyses. A kinetic study of the OxD was performed, including a cytotoxicity assay using peripheral blood mononuclear cells (PBMCs). The maximum increment of solubility was obtained at 70 mM OxD using 400 mM 2-HPßCD. SEM analyses and FTIR spectra indicated the formation of inclusion complexes. 1H-NMR presented chemical shifts that indicated 1:1 stoichiometry. Different thermal behaviors were obtained. The pharmacokinetic profile showed a short release time. Pure OxD and its inclusion complex did not exhibit cytotoxicity in PBMCs. In silico studies provided a foremost insight into the interactions between OxD and 2-HPßCD, including a higher solubility in water and an average releasing profile without toxicity in normal cells
Asunto(s)
Solubilidad/efectos de los fármacos , Ciclodextrinas/agonistas , Microscopía Electrónica de Rastreo/métodos , Espectroscopía de Resonancia Magnética/métodos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Espectroscopía de Protones por Resonancia Magnética/métodos , Antibacterianos/análisisRESUMEN
BACKGROUND: Albendazole (ABZ) is the drug of choice for the treatment of a variety of human and veterinary parasites. However, it has low aqueous solubility and low bioavailability. Cyclodextrins (CD) are pharmaceutical excipients with the ability to modulate the solubilization property of hydrophobic molecules. OBJECTIVE: The aim of the study was to analyze through in vitro and in silico studies (Autodock Vina software and CycloMolder platform) the formation of inclusion complexes between ABZ, ß-cyclodextrin (ß-CD) and its derivatives Methyl-ß-cyclodextrin (M-ß-CD) and Hydroxypropyl-ß-cyclodextrin (HP-ß-CD). METHODS: The most stable inclusion complexes were produced by the kneading method and characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), determination of the ABZ content and in vitro dissolution profile. RESULTS: Molecular modeling revealed that inclusion complexes between HP-ß-CD:ABZ (in the proportion 1:1 and 2:1) presented the lowest formation energy and the highest number of intermolecular interactions, showing that the use of more cyclodextrins does not generate gains in the stability of the complex. On the characterization tests, the complexes experimentally obtained by the kneading method demonstrated highly suggestive parameters, including ABZ in HP-ß-CD in both molar proportions, suppression of bands in the infrared spectrum, displacement of the drug's melting temperature in DSC, crystallinity halos instead of the characteristic peaks of ABZ crystals in the XRD and a release of more than 80% of ABZ in less than 5 minutes, dissolution efficiency of up to 92%. CONCLUSION: In silico studies provided a rational selection of the appropriate complexes of cyclodextrin, enabling the elaboration of more targeted complexes, decreasing time and costs for elaboration of new formulations, thereby increasing the oral biodisponibility of ABZ.
Asunto(s)
Albendazol , Ciclodextrinas , 2-Hidroxipropil-beta-Ciclodextrina , Albendazol/química , Rastreo Diferencial de Calorimetría , Ciclodextrinas/química , Humanos , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Difracción de Rayos XRESUMEN
The aim of the present work is to evaluate the effect of NaOH solution as a stress cracking agent on the thermal and tensile properties of PET and PET/ZnO composites. The solutions were applied during tensile testing and the effects were monitored by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and testing the actual mechanical properties. The rate of crystallization was increased when the samples were exposed to NaOH, as observed by both cold and melt crystallization; this is possibly due to the reduction in molar mass of the PET molecules caused by NaOH. During melting, the DSC peaks became more complex, which is probably due to the distinct macromolecular mass, as well as crystallites with different sizes and levels of perfection. According to TGA analyses, no drastic changes were observed on the thermal stability of PET due to the action of NaOH. The tensile properties were shown to decrease drastically upon exposure to NaOH, which is the main symptom of stress cracking, leading to increased fragility, as also observed in the scanning electron microscopy (SEM) images. The presence of ZnO improved PET crystallization and provided some protection against the harmful effects of NaOH.
RESUMEN
Fourteen arylsemicarbazone derivatives were synthesized and evaluated in order to find agents with potential anticancer activity. Cytotoxic screening was performed against K562, HL-60, MOLT-4, HEp-2, NCI-H292, HT-29 and MCF-7 tumor cell lines. Compounds 3c and 4a were active against the tested cancer cell lines, being more cytotoxic for the HL-60 cell line with IC50 values of 13.08 µM and 11.38 µM, respectively. Regarding the protein kinase inhibition assay, 3c inhibited seven different kinases and 4a strongly inhibited the CK1δ/ε kinase. The studied kinases are involved in several cellular functions such as proliferation, migration, cell death and cell cycle progression. Additional analysis by flow cytometry revealed that 3c and 4a caused depolarization of the mitochondrial membrane, suggesting apoptosis mediated by the intrinsic pathway. Compound 3c induced arrest in G1 phase of the cell cycle on HL-60 cells, and in the annexin V assay approximately 50% of cells were in apoptosis at the highest concentration tested (26 µM). Compound 4a inhibited cell cycle by accumulation of abnormal postmitotic cells at G1 phase and induced DNA fragmentation at the highest concentration (22 µM).
RESUMEN
Supramolecular interactions between ß-lapachone (ß-lap) and cyclodextrins (CDs) were investigated by isothermal titration calorimetry. The most favorable host: guest interaction was characterized using X-ray powder diffraction (XRD), differential scanning calorimetry and thermogravimetry (DSC/TG), spectroscopy (FT-IR), spectroscopy (2D ROESY) nuclear magnetic resonance (NMR), and molecular modeling. Phase solubility diagrams showed ß-, HP-ß-, SBE-ß-, γ-, and HP-γ-CDs at 1.5% (w/w) allowed an increase in apparent solubility of ß-lap with enhancement factors of 12.0, 10.1, 11.8, 2.4, and 2.2, respectively. ß-lap has a weak interaction with γ- and HP-γ-CDs and tends to interact more favorably with ß-CD and its derivatives, especially SBE-ß-CD (K = 4160 M-1 ; ΔG = -20.66 kJ·mol-1 ). Thermodynamic analysis suggests a hydrophobic interaction associated with the displacement of water from the cavity of the CD by the ß-lap. In addition, van der Waals forces and hydrogen bonds were responsible for the formation of complexes. Taken together, the results showed intermolecular interactions between ß-lap and SBE-ß-CD, thereby confirming the formation of the inclusion complex. Molecular docking results showed 2 main orientations in which the interaction of benzene moiety at the wider rim of the SBE-ß-CD is the most stable (average docking energy of -7.0 kcal/mol). In conclusion, ß-lap:SBE-ß-CD is proposed as an approach for use in drug delivery systems in cancer research.
Asunto(s)
Calorimetría/métodos , Ciclodextrinas/química , Modelos Moleculares , Naftoquinonas/química , Rastreo Diferencial de Calorimetría , Entropía , Cinética , Simulación del Acoplamiento Molecular , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría , Difracción de Rayos XRESUMEN
In this pioneer study, 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) was used to improve the solubility of the diffractaic acid (DA) via inclusion complex (DA:HP-ß-CD). Subsequently, DA:HP-ß-CD was incorporated into poly-ε-caprolactone (PCL) microspheres (DA:HP-ß-CD-MS). Microspheres containing DA (DA-MS) or DA:HP-ß-CD (DA:HP-ß-CD-MS) were prepared using the multiple W/O/W emulsion-solvent evaporation technique. The phase-solubility diagram of DA in HP-ß-CD (10-50mM) showed an AL type curve with a stability constant K1:1=821M-1. 1H NMR, FTIR, X-ray diffraction and thermal analysis showed changes in the molecular environment of DA in DA:HP-ß-CD. The molecular modeling approach suggests a guest-host complex formation between the carboxylic moiety of both DA and the host (HP-ß-CD). The mean particle size of the microspheres were ∅DA-MS=5.23±1.65µm and ∅DA:HP-ß-CD-MS=4.11±1.39µm, respectively. The zeta potential values of the microspheres were ζDA-MS=-7.85±0.32mV and ζDA:HP-ß-CD-MS=-6.93±0.46mV. Moreover, the encapsulation of DA:HP-ß-CD into microspheres resulted in a more slower release (k2=0.042±0.001; r2=0.996) when compared with DA-MS (k2=0.183±0.005; r2=0.996). The encapsulation of DA or DA:HP-ß-CD into microspheres reduced the cytotoxicity of DA (IC50=43.29µM) against Vero cells (IC50 of DA-MS=108.48µM and IC50 of DA:HP-ß-CD-MS=142.63µM).
Asunto(s)
Anisoles/farmacología , Hidroxibenzoatos/farmacología , Microesferas , Modelos Moleculares , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Animales , Anisoles/química , Rastreo Diferencial de Calorimetría , Muerte Celular/efectos de los fármacos , Chlorocebus aethiops , Concentración de Iones de Hidrógeno , Hidroxibenzoatos/química , Cinética , Microscopía Electrónica de Rastreo , Conformación Molecular , Tamaño de la Partícula , Poliésteres/química , Polvos , Espectroscopía de Protones por Resonancia Magnética , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Termogravimetría , Células Vero , Difracción de Rayos XRESUMEN
Peroxisome proliferator-activated receptor gamma (PPARγ) regulates multiple pathways involved in the pathogenesis of obesity and atherosclerosis. Here, we evaluated the therapeutic potential of GQ-177, a new thiazolidinedione, on diet-induced obesity and atherosclerosis. The intermolecular interaction between PPARγ and GQ-177 was examined by virtual docking and PPAR activation was determined by reporter gene assay identifying GQ-177 as a partial and selective PPARγ agonist. For the evaluation of biological activity of GQ-177, low-density lipoprotein receptor-deficient (LDLr(-/-)) C57/BL6 mice were fed either a high fat diabetogenic diet (diet-induced obesity), or a high fat atherogenic diet, and treated with vehicle, GQ-177 (20mg/kg/day), pioglitazone (20mg/kg/day, diet-induced obesity model) or rosiglitazone (15mg/kg/day, atherosclerosis model) for 28 days. In diet-induced obesity mice, GQ-177 improved insulin sensitivity and lipid profile, increased plasma adiponectin and GLUT4 mRNA in adipose tissue, without affecting body weight, food consumption, fat accumulation and bone density. Moreover, GQ-177 enhanced hepatic mRNA levels of proteins involved in lipid metabolism. In the atherosclerosis mice, GQ-177 inhibited atherosclerotic lesion progression, increased plasma HDL and mRNA levels of PPARγ and ATP-binding cassette A1 in atherosclerotic lesions. GQ-177 acts as a partial PPARγ agonist that improves obesity-associated insulin resistance and dyslipidemia with atheroprotective effects in LDLr(-/-) mice.
Asunto(s)
Aterosclerosis/metabolismo , Obesidad/metabolismo , PPAR gamma/agonistas , PPAR gamma/metabolismo , Receptores de LDL/genética , Sulfonas/farmacología , Tiazolidinedionas/farmacología , Adiponectina/genética , Tejido Adiposo/efectos de los fármacos , Tejido Adiposo/metabolismo , Animales , Aorta Torácica/patología , Aterosclerosis/sangre , Aterosclerosis/tratamiento farmacológico , Aterosclerosis/patología , Densidad Ósea , Línea Celular , HDL-Colesterol/sangre , Factores de Crecimiento de Fibroblastos/genética , Transportador de Glucosa de Tipo 4/genética , Humanos , Leptina/genética , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratones Noqueados , Modelos Moleculares , Miocardio/metabolismo , Obesidad/sangre , Obesidad/tratamiento farmacológico , Obesidad/patología , Sulfonas/uso terapéutico , Tiazolidinedionas/uso terapéuticoRESUMEN
The present work reports the synthesis and evaluation of the antitumour and immunomodulatory properties of new phthalimides derivatives designed to explore molecular hybridization and bioisosterism approaches between thalidomide, thiosemicarbazone, thiazolidinone and thiazole series. Twenty-seven new molecules were assessed for their immunosuppressive effect toward TNFα, IFNγ, IL-2 and IL-6 production and antiproliferative activity. The best activity profile was observed for the (6a-f) series, which presents phthalyl and thiazolidinone groups.
Asunto(s)
Antineoplásicos/farmacología , Diseño de Fármacos , Inmunomodulación , Ftalimidas/farmacología , Animales , Antineoplásicos/síntesis química , Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Cristalografía por Rayos X , Citocinas/análisis , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Linfocitos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Modelos Moleculares , Estructura Molecular , Ftalimidas/síntesis química , Ftalimidas/química , Relación Estructura-ActividadRESUMEN
The present work reports on the synthesis, anti-Trypanosoma cruzi activities and docking studies of a novel series of 2-(pyridin-2-yl)-1,3-thiazoles derived from 2-pyridine thiosemicarbazone. The majority of these compounds are potent cruzain inhibitors and showed excellent inhibition on the trypomastigote form of the parasite, and the resulting structure-activity relationships are discussed. Together, these data present a novel series of thiazolyl hydrazones with potential effects against Chagas disease and they could be important leads in continuing development against Chagas disease.
Asunto(s)
Diseño de Fármacos , Piridinas/farmacología , Tiazoles/farmacología , Tripanocidas/química , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Estructura Molecular , Pruebas de Sensibilidad Parasitaria , Piridinas/síntesis química , Piridinas/química , Relación Estructura-Actividad , Tiazoles/síntesis química , Tiazoles/química , Tripanocidas/síntesis químicaRESUMEN
Pharmacological treatment of Chagas disease is based on benznidazole, which displays poor efficacy when administered during the chronic phase of infection. Therefore, the development of new therapeutic options is needed. This study reports on the structural design and synthesis of a new class of anti-Trypanosoma cruzi thiazolidinones (4 a-p). (2-[2-Phenoxy-1-(4-bromophenyl)ethylidene)hydrazono]-5-ethylthiazolidin-4-one (4 h) and (2-[2-phenoxy-1-(4-phenylphenyl)ethylidene)hydrazono]-5-ethylthiazolidin-4-one (4 l) were the most potent compounds, resulting in reduced epimastigote proliferation and were toxic for trypomastigotes at concentrations below 10â µM, while they did not display host cell toxicity up to 200â µM. Thiazolidinone 4 h was able to reduce the in vitro parasite burden and the blood parasitemia in mice with similar potency to benznidazole. More importantly, T.â cruzi infection reduction was achieved without exhibiting mouse toxicity. Regarding the molecular mechanism of action, these thiazolidinones did not inhibit cruzain activity, which is the major trypanosomal protease. However, investigating the cellular mechanism of action, thiazolidinones altered Golgi complex and endoplasmic reticulum (ER) morphology, produced atypical cytosolic vacuoles, as well as induced necrotic parasite death. This structural design employed for the new anti-T.â cruzi thiazolidinones (4 a-p) led to the identification of compounds with enhanced potency and selectivity compared to first-generation thiazolidinones. These compounds did not inhibit cruzain activity, but exhibited strong antiparasitic activity by acting as parasiticidal agents and inducing a necrotic parasite cell death.
Asunto(s)
Diseño de Fármacos , Hidrazinas/síntesis química , Tiazolidinedionas/síntesis química , Tiazolidinas/química , Tripanocidas/síntesis química , Animales , Células Cultivadas , Cristalografía por Rayos X , Cisteína Endopeptidasas/metabolismo , Retículo Endoplásmico/efectos de los fármacos , Femenino , Aparato de Golgi/efectos de los fármacos , Hidrazinas/química , Hidrazinas/farmacología , Macrófagos/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Conformación Molecular , Simulación del Acoplamiento Molecular , Estructura Terciaria de Proteína , Proteínas Protozoarias/antagonistas & inhibidores , Proteínas Protozoarias/metabolismo , Bazo/citología , Bazo/efectos de los fármacos , Relación Estructura-Actividad , Tiazolidinedionas/química , Tiazolidinedionas/farmacología , Tiazolidinas/síntesis química , Tiazolidinas/farmacología , Tripanocidas/química , Tripanocidas/farmacología , Trypanosoma cruzi/efectos de los fármacosRESUMEN
Mammalian natriuretic peptides (NPs) have been extensively investigated for use as therapeutic agents in the treatment of cardiovascular diseases. Here, we describe the isolation, sequencing and tridimensional homology modeling of the first C-type natriuretic peptide isolated from scorpion venom. In addition, its effects on the renal function of rats and on the mRNA expression of natriuretic peptide receptors in the kidneys are delineated. Fractionation of Tityus serrulatus venom using chromatographic techniques yielded a peptide with a molecular mass of 2190.64 Da, which exhibited the pattern of disulfide bridges that is characteristic of a C-type NP (TsNP, T. serrulatus Natriuretic Peptide). In the isolated perfused rat kidney assay, treatment with two concentrations of TsNP (0.03 and 0.1 µg/mL) increased the perfusion pressure, glomerular filtration rate and urinary flow. After 60 min of treatment at both concentrations, the percentages of sodium, potassium and chloride transport were decreased, and the urinary cGMP concentration was elevated. Natriuretic peptide receptor-A (NPR-A) mRNA expression was down regulated in the kidneys treated with both concentrations of TsNP, whereas NPR-B, NPR-C and CG-C mRNAs were up regulated at the 0.1 µg/mL concentration. In conclusion, this work describes the isolation and modeling of the first natriuretic peptide isolated from scorpion venom. In addition, examinations of the renal actions of TsNP indicate that its effects may be related to the activation of NPR-B, NPR-C and GC-C.
Asunto(s)
Riñón/efectos de los fármacos , Péptido Natriurético Tipo-C/aislamiento & purificación , Venenos de Escorpión/aislamiento & purificación , Escorpiones/química , Secuencia de Aminoácidos , Animales , Brasil , GMP Cíclico/genética , GMP Cíclico/metabolismo , Regulación hacia Abajo , Tasa de Filtración Glomerular , Riñón/metabolismo , Masculino , Datos de Secuencia Molecular , Péptido Natriurético Tipo-C/química , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Receptores del Factor Natriurético Atrial/genética , Receptores del Factor Natriurético Atrial/metabolismo , Venenos de Escorpión/química , Alineación de Secuencia , Regulación hacia ArribaRESUMEN
The compound (5Z)-5-[(5-bromo-1H-indol-3-yl)methylene]-3-(4-chlorobenzyl)-thiazolidine-2,4-dione (LYSO-7) was synthesised in order to obtain a new type of anti-inflammatory drug, designed with hybrid features to inhibit cyclooxygenase (COX) and also to activate peroxisome proliferator-activated receptor (PPAR). Results obtained from docking (in silico) studies corroborated with experimental data, showing the potential affinity between the studied ligand and targets. The specificity of LYSO-7 for COX-enzymes was detected by the inhibition of COX-1 and COX-2 activities by 30% and 20%, respectively. In transactivation reporter gene assays LYSO-07 showed a pan partial agonist effect on the three PPAR subtypes (PPARγ, PPARα and PPARß/δ). The agonist action on PPARγ was also observed by a pharmacological approach, as the reduction in the Escherichia coli lipopolysaccharide (LPS)-induced interleukin 1 beta (IL-1ß) secretion and nitric oxide (NO) production by mouse neutrophils was blocked by GW9962, a specific PPARγ antagonist. Additionally, the in vivo effect was measured by reduced carrageenan-induced neutrophil influx into the subcutaneous tissue of mice. Taken together, these data show that LYSO-7 displays a potent in vivo anti-inflammatory effect during the innate acute response, which is dependent on its associated COX inhibitory activities and PPAR activation.
Asunto(s)
Antiinflamatorios/farmacología , Inhibidores de la Ciclooxigenasa/farmacología , Indoles/farmacología , Receptores Activados del Proliferador del Peroxisoma/agonistas , Tiazolidinedionas/farmacología , Animales , Carragenina , Movimiento Celular/efectos de los fármacos , Células HeLa , Humanos , Inflamación/inducido químicamente , Inflamación/tratamiento farmacológico , Leucocitos/efectos de los fármacos , Leucocitos/fisiología , Masculino , Ratones , Modelos MolecularesRESUMEN
We modified the thiazolidinic ring at positions N3, C4, and C5, yielding compounds 6-24. Compounds with a phenyl at position N3, 15-19, 22-24, exhibited better inhibitory properties for cruzain and against the parasite than 2-iminothiazolidin-4-one 5. We were able to identify one high-efficacy trypanocidal compound, 2-minothiazolidin-4-one 18, which inhibited the activity of cruzain and the proliferation of epimastigotes and was cidal for trypomastigotes but was not toxic for splenocytes. Having located some of the structural determinants of the trypanocidal properties, we subsequently wished to determine if the exchange of the thiazolidine for a thiazole ring leaves the functional properties unaffected. We therefore tested thiazoles 26-45 and observed that they did not inhibit cruzain, but they exhibited trypanocidal effects. Parasite development was severely impaired when treated with 18, thus reinforcing the notion that this class of heterocycles can lead to useful cidal agents for Chagas disease.
Asunto(s)
Enfermedad de Chagas/tratamiento farmacológico , Iminas/síntesis química , Tiazolidinas/síntesis química , Tripanocidas/síntesis química , Trypanosoma cruzi/efectos de los fármacos , Animales , Proliferación Celular/efectos de los fármacos , Simulación por Computador , Cisteína Endopeptidasas/metabolismo , Femenino , Iminas/química , Iminas/farmacología , Ratones , Ratones Endogámicos BALB C , Modelos Moleculares , Unión Proteica , Proteínas Protozoarias/antagonistas & inhibidores , Proteínas Protozoarias/metabolismo , Bazo/citología , Estereoisomerismo , Relación Estructura-Actividad , Tiazolidinas/química , Tiazolidinas/farmacología , Tripanocidas/química , Tripanocidas/farmacología , Trypanosoma cruzi/metabolismoRESUMEN
LPSF/AC04 (5Z)-[5-acridin-9-ylmethylene-3-(4-methyl-benzyl)-thiazolidine-2,4-dione] is an acridine-based derivative, part of a series of new anticancer agents synthesized for the purpose of developing more effective and less toxic anticancer drugs. However, the use of LPSF/AC04 is limited due to its low solubility in aqueous solutions. To overcome this problem, we investigated the interaction of LPSF/AC04 with hydroxypropyl-ß-cyclodextrin (HP-ß-CyD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CyD) in inclusion complexes and determine which of the complexes formed presents the most significant interactions. In this paper, we report the physical characterization of the LPSF/AC04-HP-CyD inclusion complexes by thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy absorption, Raman spectroscopy, (1)HNMR, scanning electron microscopy, and by molecular modeling approaches. In addition, we verified that HP-ß-CyD complexation enhances the aqueous solubility of LPSF/AC04, and a significant increase in the antiproliferative activity of LPSF/AC04 against cell lines can be achieved by the encapsulation into liposomes. These findings showed that the nanoencapsulation of LPSF/AC04 and LPSF/AC04-HP-CyD inclusion complexes in liposomes leads to improved drug penetration into the cells and, as a result, an enhancement of cytotoxic activity. Further in vivo studies comparing free and encapsulated LPSF/AC04 will be undertaken to support this investigation.
Asunto(s)
Acridinas/química , Acridinas/farmacología , Antineoplásicos/química , Antineoplásicos/farmacología , Liposomas/química , Tiazolidinedionas/química , Tiazolidinedionas/farmacología , beta-Ciclodextrinas/química , gamma-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Absorción , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Estabilidad de Medicamentos , Excipientes/química , Humanos , Solubilidad , Agua/químicaRESUMEN
BACKGROUND: The intermetatarsal angle (IMA), the hallux valgus angle (HVA), and the lateral sesamoid malalignment in relation to the first metatarsal are among the most commonly employed parameters to estimate the severity of the deformity. The aim of this study was to compare HV angular measurements and a linear measurement among 4 observers to determine its intraobserver and interobserver reliability, to find out whether this linear measurement technique is more reproducible than those already-described angular measurements. METHODS: The IMA, the HVA, and the distance between the lateral cortex of the first metatarsal and the lateral cortex of the lateral sesamoid bone were measured from 50 standing, nonoperated hallux valgus feet. Radiographs were shuffled and reforwarded to the observers at a minimum interval of 30 days for a new measurement. RESULTS: When considering 2° of difference as significant, IMA and HVA measurements were not precise, showing low reproducibility for both intraobserver and interobserver assessment. Regarding the distance between the first metatarsal lateral cortex and the lateral sesamoid lateral cortex, when considering differences greater than 2 mm as significant, we observed higher precision and higher reproducibility. CONCLUSIONS: Angular measurements of hallux valgus deformity in anteroposterior standing radiographs that are manually performed with a goniometer are not precise and have low reproducibility. The linear measurement of the distance between the lateral cortices of the first metatarsal head and the lateral sesamoid demonstrated higher precision and higher reproducibility, and may be a cheap form to assess the correct indication of a distal osteotomy. LEVELS OF EVIDENCE: Diagnostic, Level II.
Asunto(s)
Hallux Valgus/diagnóstico por imagen , Hallux Valgus/patología , Variaciones Dependientes del Observador , Artrometría Articular , Humanos , Huesos Metatarsianos/diagnóstico por imagen , Huesos Metatarsianos/patología , Radiografía , Reproducibilidad de los Resultados , Huesos Sesamoideos/diagnóstico por imagen , Huesos Sesamoideos/patologíaRESUMEN
Secretory phospholipases A(2) (sPLA(2)) exert proinflammatory actions through lipid mediators. These enzymes have been found to be elevated in many inflammatory disorders such as rheumatoid arthritis, sepsis, and atherosclerosis. The aim of this study was to evaluate the effect of harpalycin 2 (Har2), an isoflavone isolated from Harpalyce brasiliana Benth., in the enzymatic, edematogenic, and myotoxic activities of sPLA(2) from Bothrops pirajai, Crotalus durissus terrificus, Apis mellifera, and Naja naja venoms. Har2 inhibits all sPLA(2) tested. PrTX-III (B. pirajai venom) was inhibited at about 58.7%, Cdt F15 (C. d. terrificus venom) at 78.8%, Apis (from bee venom) at 87.7%, and Naja (N. naja venom) at 88.1%. Edema induced by exogenous sPLA(2) administration performed in mice paws showed significant inhibition by Har2 at the initial step. In addition, Har2 also inhibited the myotoxic activity of these sPLA(2)s. In order to understand how Har2 interacts with these enzymes, docking calculations were made, indicating that the residues His48 and Asp49 in the active site of these enzymes interacted powerfully with Har2 through hydrogen bonds. These data pointed to a possible anti-inflammatory activity of Har2 through sPLA(2) inhibition.
RESUMEN
BACKGROUND: Harpalycin 2 (HP-2) is an isoflavone isolated from the leaves of Harpalyce brasiliana Benth., a snakeroot found in northeast region of Brazil and used in folk medicine to treat snakebite. Its leaves are said to be anti-inflammatory. Secretory phospholipases A2 are important toxins found in snake venom and are structurally related to those found in inflammatory conditions in mammals, as in arthritis and atherosclerosis, and for this reason can be valuable tools for searching new anti-phospholipase A2 drugs. METHODS: HP-2 and piratoxin-III (PrTX-III) were purified through chromatographic techniques. The effect of HP-2 in the enzymatic activity of PrTX-III was carried out using 4-nitro-3-octanoyloxy-benzoic acid as the substrate. PrTX-III induced platelet aggregation was inhibited by HP-2 when compared to aristolochic acid and p-bromophenacyl bromide (p-BPB). In an attempt to elucidate how HP-2 interacts with PrTX-III, mass spectrometry, circular dichroism and intrinsic fluorescence analysis were performed. Docking scores of the ligands (HP-2, aristolochic acid and p-BPB) using PrTX-III as target were also calculated. RESULTS: HP-2 inhibited the enzymatic activity of PrTX-III (IC50 11.34 ± 0.28 µg/mL) although it did not form a stable chemical complex in the active site, since mass spectrometry measurements showed no difference between native (13,837.34 Da) and HP-2 treated PrTX-III (13,856.12 Da). A structural analysis of PrTX-III after treatment with HP-2 showed a decrease in dimerization and a slight protein unfolding. In the platelet aggregation assay, HP-2 previously incubated with PrTX-III inhibited the aggregation when compared with untreated protein. PrTX-III chemical treated with aristolochic acid and p-BPB, two standard PLA2 inhibitors, showed low inhibitory effects when compared with the HP-2 treatment. Docking scores corroborated these results, showing higher affinity of HP-2 for the PrTX-III target (PDB code: 1GMZ) than aristolochic acid and p-BPB. HP-2 previous incubated with the platelets inhibits the aggregation induced by untreated PrTX-III as well as arachidonic acid. CONCLUSION: HP-2 changes the structure of PrTX-III, inhibiting the enzymatic activity of this enzyme. In addition, PrTX-III platelet aggregant activity was inhibited by treatment with HP-2, p-BPB and aristolochic acid, and these results were corroborated by docking scores.
Asunto(s)
Benzodioxoles/farmacología , Bothrops , Venenos de Crotálidos/enzimología , Inhibidores Enzimáticos/farmacología , Fabaceae/química , Fosfolipasas A2 Grupo II/antagonistas & inhibidores , Isoflavonas/farmacología , Agregación Plaquetaria/efectos de los fármacos , Acetofenonas/farmacología , Animales , Ácidos Aristolóquicos/farmacología , Benzodioxoles/aislamiento & purificación , Benzodioxoles/uso terapéutico , Brasil , Inhibidores Enzimáticos/aislamiento & purificación , Inhibidores Enzimáticos/uso terapéutico , Fosfolipasas A2 Grupo II/química , Humanos , Isoflavonas/aislamiento & purificación , Isoflavonas/uso terapéutico , Nitrobenzoatos/metabolismo , Fitoterapia , Extractos Vegetales/química , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico , Hojas de la Planta , Proteínas de Reptiles/antagonistas & inhibidores , Proteínas de Reptiles/química , Mordeduras de Serpientes/tratamiento farmacológico , Mordeduras de Serpientes/enzimologíaRESUMEN
The aim of this study was to encapsulate lapachone (ß-lap) or inclusion complex (ß-lap:HPß-CD) in liposomes and to evaluate their physicochemical characteristics. In addition, the investigation of the main aspects of the interaction between ß-lap and 2-hydroxypropyl-ß-cyclodextrin (HPß-CD), using both experimental and molecular modeling approaches was discussed. Furthermore, the in vitro drug release kinetics was evaluated. First, a phase solubility study of ß-lap in HPß-CD was performed and the ß-lap:HPß-CD was prepared by the freeze-drying technique. A 302-fold increase of solubility was achieved for ß-lap in HPß-CD solution with a constant of association K(1:1) of 961 M(-1) and a complexation efficiency of ß-lap of 0.1538. (1)H NMR, TG, DSC, IR, Raman and SEM indicated a change in the molecular environment of ß-lap in the inclusion complex. Molecular modeling confirms these results suggesting that ß-lap was included in the cavity of HPß-CD, with an intermolecular interaction energy of -23.67 kJ mol(-1). ß-lap:HPß-CD and ß-lap-loaded liposomes presented encapsulation efficiencies of 93% and 97%, respectively. The kinetic rate constants of 183.95±1.82 µg/h and 216.25±2.34 µg/h were calculated for ß-lap and ß-lap:HPß-CD-loaded liposomes, respectively. In conclusion, molecular modeling elucidates the formation of the inclusion complex, stabilized through hydrogen bonds, and the encapsulation of ß-lap and ß-lap:HPß-CD into liposomes could provide an alternative means leading eventually to its use in cancer research.
Asunto(s)
Adyuvantes Farmacéuticos/química , Modelos Moleculares , Naftoquinonas/administración & dosificación , Naftoquinonas/química , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Composición de Medicamentos , Liofilización , Liposomas , Microscopía Electrónica de Rastreo , Estructura Molecular , Transición de Fase , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Propiedades de SuperficieRESUMEN
As polyphenolic compounds isolated from plants extracts, flavonoids have been applied to various pharmaceutical uses in recent decades due to their anti-inflammatory, cancer preventive, and cardiovascular protective activities. In this study, we evaluated the effects of the flavonoid quercetin on Crotalus durissus terrificus secretory phospholipase A2 (sPLA2), an important protein involved in the release of arachidonic acid from phospholipid membranes. The protein was chemically modified by treatment with quercetin, which resulted in modifications in the secondary structure as evidenced through circular dichroism. In addition, quercetin was able to inhibit the enzymatic activity and some pharmacological activities of sPLA2, including its antibacterial activity, its ability to induce platelet aggregation, and its myotoxicity by approximately 40%, but was not able to reduce the inflammatory and neurotoxic activities of sPLA2. These results suggest the existence of two pharmacological sites in the protein, one that is correlated with the enzymatic site and another that is distinct from it. We also performed molecular docking to better understand the possible interactions between quercetin and sPLA2. Our docking data showed the existence of hydrogen-bonded, polar interactions and hydrophobic interactions, suggesting that other flavonoids with similar structures could bind to sPLA2. Further research is warranted to investigate the potential use of flavonoids as sPLA2 inhibitors.