A series of novel acridine N-acylhydrazone derivatives have been synthesized as potential topoisomerase I/II inhibitors, and their binding (calf thymus DNA-ctDNA and human serum albumin-HSA) and biological activities as potential anticancer agents on proliferation of A549 and CCD-18Co have been evaluated. The acridine-DNA complex 3b (-F) displayed the highest Kb value (Kb = 3.18 × 103 M-1). The HSA-derivatives interactions were studied by fluorescence quenching spectra. This method was used for the calculation of characteristic binding parameters. In the presence of warfarin, the binding constant values were found to decrease (KSV = 2.26 M-1, Kb = 2.54 M-1), suggesting that derivative 3a could bind to HSA at Sudlow site I. The effect of tested derivatives on metabolic activity of A549 cells evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide or MTT assay decreased as follows 3b(-F) > 3a(-H) > 3c(-Cl) > 3d(-Br). The derivatives 3c and 3d in vitro act as potential dual inhibitors of hTopo I and II with a partial effect on the metabolic activity of cancer cells A594. The acridine-benzohydrazides 3a and 3c reduced the clonogenic ability of A549 cells by 72% or 74%, respectively. The general results of the study suggest that the novel compounds show potential for future development as anticancer agents.
- MeSH
- akridiny chemie MeSH
- antitumorózní látky * chemie MeSH
- inhibitory topoisomerasy II farmakologie MeSH
- interkalátory MeSH
- lidé MeSH
- lidský sérový albumin chemie MeSH
- vazebná místa MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The interactions of epoxiconazole and prothioconazole with human serum albumin and bovine serum albumin were investigated using spectroscopic methods complemented with molecular modeling. Spectroscopic techniques showed the formation of pesticide/serum albumin complexes with the static type as the dominant mechanism. The association constants ranged from 3.80 × 104-6.45 × 105 L/mol depending on the pesticide molecule (epoxiconazole, prothioconazole) and albumin type (human or bovine serum albumin). The calculated thermodynamic parameters revealed that the binding of pesticides into serum albumin macromolecules mainly depended on hydrogen bonds and van der Waals interactions. Synchronous fluorescence spectroscopy and the competitive experiments method showed that pesticides bind to subdomain IIA, near tryptophan; in the case of bovine serum albumin also on the macromolecule surface. Concerning prothioconazole, we observed the existence of an additional binding site at the junction of domains I and III of serum albumin macromolecules. These observations were corroborated well by molecular modeling predictions. The conformation changes in secondary structure were characterized by circular dichroism, three-dimensional fluorescence, and UV/VIS absorption methods.
- MeSH
- cirkulární dichroismus metody MeSH
- epoxidové sloučeniny chemie MeSH
- fluorescenční spektrometrie metody MeSH
- hydrofobní a hydrofilní interakce MeSH
- lidé MeSH
- lidský sérový albumin chemie MeSH
- pesticidy chemie MeSH
- sekundární struktura proteinů MeSH
- sérový albumin hovězí chemie MeSH
- simulace molekulového dockingu metody MeSH
- skot MeSH
- statická elektřina MeSH
- teplota MeSH
- triazoly chemie MeSH
- vazba proteinů MeSH
- vazebná místa MeSH
- vodíková vazba MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The effective concentration of a drug in the blood, i.e. the concentration of a free drug in the blood, is influenced by the strength of drug binding onto plasma proteins. Besides its efficacy, these interactions subsequently influence the liberation, absorption, distribution, metabolism, excretion, and toxicological properties of the drug. It is important to not only determine the binding strength and stoichiometry, but also the binding site of a drug on the plasma protein molecule, because the co-administration of drugs with the same binding site can affect the above-mentioned concentration and as a result the pharmacological behavior of the drugs and lead to side effects caused by the change in free drug concentration, its toxicity. In this study, the binding characteristics of six drugs with human serum albumin, the most abundant protein in human plasma, were determined by capillary electrophoresis-frontal analysis, and the obtained values of binding parameters were compared with the literature data. The effect of several drugs and site markers on the binding of l-tryptophan and lidocaine to human serum albumin was investigated in subsequent displacement studies which thus demonstrated the usability of capillary electrophoresis as an automated high-throughput screening method for drug-protein binding studies.
- MeSH
- chlorpropamid analýza farmakologie MeSH
- diklofenak analýza farmakologie MeSH
- elektroforéza kapilární MeSH
- fenylbutazon analýza farmakologie MeSH
- flurbiprofen analýza farmakologie MeSH
- ibuprofen analýza farmakologie MeSH
- lidé MeSH
- lidokain antagonisté a inhibitory chemie MeSH
- lidský sérový albumin chemie MeSH
- tolbutamid analýza farmakologie MeSH
- tryptofan antagonisté a inhibitory chemie MeSH
- vazebná místa účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Flavonoids are abundant polyphenols in nature. They are extensively biotransformed in enterocytes and hepatocytes, where conjugated (methyl, sulfate, and glucuronide) metabolites are formed. However, bacterial microflora in the human intestines also metabolize flavonoids, resulting in the production of smaller phenolic fragments (e.g., hydroxybenzoic, hydroxyacetic and hydroxycinnamic acids, and hydroxybenzenes). Despite the fact that several colonic metabolites appear in the circulation at high concentrations, we have only limited information regarding their pharmacodynamic effects and pharmacokinetic interactions. Therefore, in this in vitro study, we investigated the interactions of 24 microbial flavonoid metabolites with human serum albumin and cytochrome P450 (CYP2C9, 2C19, and 3A4) enzymes. Our results demonstrated that some metabolites (e.g., 2,4-dihydroxyacetophenone, pyrogallol, O-desmethylangolensin, and 2-hydroxy-4-methoxybenzoic acid) form stable complexes with albumin. However, the compounds tested did not considerably displace Site I and II marker drugs from albumin. All CYP isoforms examined were significantly inhibited by O-desmethylangolensin; nevertheless, only its effect on CYP2C9 seems to be relevant. Furthermore, resorcinol and phloroglucinol showed strong inhibitory effects on CYP3A4. Our results demonstrate that, besides flavonoid aglycones and their conjugated derivatives, some colonic metabolites are also able to interact with proteins involved in the pharmacokinetics of drugs.
- MeSH
- erytrocyty enzymologie MeSH
- flavonoidy * chemie metabolismus MeSH
- hepatocyty enzymologie MeSH
- lidé MeSH
- lidský sérový albumin * chemie metabolismus MeSH
- systém (enzymů) cytochromů P-450 * chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Studies of interactions between pesticides and target mammalian proteins are important steps toward understanding the pesticide's toxicity. Using calorimetric and spectroscopic methods, the interaction between triazole fungicide tebuconazole and human serum albumin has been investigated. The spectroscopic techniques showed that fluorescence quenching of human serum albumin by tebuconazole was the result of the formation of tebuconazole/human serum albumin complex with the static type as the dominant mechanism. The association constant was found to be 8.51 × 103 L/mol. The thermodynamic parameters were obtained as ΔH = -56.964 kJ/mol, ΔS = -115.98 J/mol·K. The main active interactions forming the tebuconazole/human serum albumin complex were identified as the interplay between hydrogen bonds and/or van der Waals forces, based on thermodynamic experiments. These binding modes were corroborated well by the predictions of molecular modeling. Hydrogen bonding of tebuconazole with Arg222, Ala215 and Ala291 of human serum albumin played a relevant role in binding. The conformation changes in secondary structure were characterized by circular dichroism and 3D fluorescence spectra.
- MeSH
- diferenciální skenovací kalorimetrie MeSH
- fluorescenční spektrometrie MeSH
- fungicidy průmyslové farmakologie MeSH
- ibuprofen farmakologie MeSH
- ketoprofen farmakologie MeSH
- lidé MeSH
- lidský sérový albumin chemie metabolismus MeSH
- simulace molekulového dockingu MeSH
- termodynamika MeSH
- triazoly chemie farmakologie MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Nitro-fatty acids modulate inflammatory and metabolic stress responses, thus displaying potential as new drug candidates. Herein, we evaluate the redox behavior of nitro-oleic acid (NO2-OA) and its ability to bind to the fatty acid transporter human serum albumin (HSA). The nitro group of NO2-OA underwent electrochemical reduction at -0.75 V at pH 7.4 in an aqueous milieu. Based on observations of the R-NO2 reduction process, the stability and reactivity of NO2-OA was measured in comparison to oleic acid (OA) as the negative control. These electrochemically-based results were reinforced by computational quantum mechanical modeling. DFT calculations indicated that both the C9-NO2 and C10-NO2 positional isomers of NO2-OA occurred in two conformers with different internal angles (69° and 110°) between the methyl- and carboxylate termini. Both NO2-OA positional isomers have LUMO energies of around -0.7 eV, affirming the electrophilic properties of fatty acid nitroalkenes. In addition, the binding of NO2-OA and OA with HSA revealed a molar ratio of ~7:1 [NO2-OA]:[HSA]. These binding experiments were performed using both an electrocatalytic approach and electron paramagnetic resonance (EPR) spectroscopy using 16-doxyl stearic acid. Using a Fe(DTCS)2 spin-trap, EPR studies also showed that the release of the nitro moiety of NO2-OA resulted in the formation of nitric oxide radical. Finally, the interaction of NO2-OA with HSA was monitored via Tyr and Trp residue electro-oxidation. The results indicate that not only non-covalent binding but also NO2-OA-HSA adduction mechanisms should be taken into consideration. This study of the redox properties of NO2-OA is applicable to the characterization of other electrophilic mediators of biological and pharmacological relevance.
- MeSH
- dusíkaté sloučeniny chemie metabolismus MeSH
- kyselina dusičná chemie metabolismus MeSH
- lidé MeSH
- lidský sérový albumin chemie metabolismus MeSH
- mastné kyseliny chemie metabolismus MeSH
- oxid dusnatý chemie metabolismus MeSH
- oxidace-redukce * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
BACKGROUND: The action spectrum for bilirubin photodegradation has been intensively studied. However, questions still remain regarding which light wavelength most efficiently photodegrades bilirubin. In this study, we determined the in vitro effects of different irradiation wavelength ranges on bilirubin photodegradation. METHODS: In our in vitro method, normalized absolute irradiance levels of 4.2 × 1015 photons/cm2/s from light-emitting diodes (ranging from 390-530 nm) and 10-nm band-pass filters were used to irradiate bilirubin solutions (25 mg/dL in 4% human serum albumin). Bilirubin and its major photoisomer concentrations were determined; the half-life time of bilirubin (t1/2) was calculated for each wavelength range, and the spectral characteristics for bilirubin photodegradation products were obtained for key wavelengths. RESULTS: The in vitro photodegradation of bilirubin at 37 °C decreased linearly as the wavelength was increased from 390 to 500 nm with t1/2 decreasing from 63 to 17 min, respectively. At 460 ± 10 nm, a significantly lower rate of photodegradation and thus higher t1/2 (31 min) than that at 500 nm (17 min) was demonstrated. CONCLUSION: In our system, the optimum bilirubin photodegradation and lumirubin production rates occurred between 490 and 500 nm. Spectra shapes were remarkably similar, suggesting that lumirubin production was the major process of bilirubin photodegradation.
- MeSH
- bilirubin analogy a deriváty krev chemie účinky záření MeSH
- fotolýza účinky záření MeSH
- fototerapie metody MeSH
- isomerie MeSH
- lidé MeSH
- lidský sérový albumin chemie účinky záření MeSH
- novorozenec MeSH
- novorozenecká hyperbilirubinemie krev terapie MeSH
- spektrofotometrie MeSH
- světlo * MeSH
- techniky in vitro MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nanoparticles (NPs) that form by self-assembly of amphiphilic poly(N-(2-hydroxypropyl)-methacrylamide) (pHPMA) copolymers bearing cholesterol side groups are potential drug carriers for solid tumor treatment. Here, we investigate their behavior in solutions of human serum albumin (HSA) in phosphate buffered saline. Mixed solutions of NPs, from polymer conjugates with or without the anticancer drug doxorubicin (Dox) bound to them, and HSA at concentrations up to the physiological value are characterized by synchrotron small-angle X-ray scattering and isothermal titration calorimetry. When Dox is absent, a small amount of HSA molecules bind to the cholesterol groups that form the core of the NPs by diffusing through the loose pHPMA shell or get caught in meshes formed by the pHPMA chains. These interactions are strongly hindered by the presence of Dox, which is distributed in the pHPMA shell, meaning that the delivery of Dox by the NPs in the human body is not affected by the presence of HSA.
- MeSH
- cholesterol chemie farmakokinetika MeSH
- doxorubicin chemie farmakokinetika MeSH
- kyseliny polymethakrylové chemie farmakokinetika MeSH
- lidé MeSH
- lidský sérový albumin chemie farmakokinetika MeSH
- nádory farmakoterapie metabolismus MeSH
- nanočástice chemie MeSH
- systémy cílené aplikace léků metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A series of new Zn(II) complexes with flufenamic acid (flu) has been synthesized, namely [Zn3(dmso)2(flu)6] (1), [Zn3(flu)6(py)2] (2), [Zn(flu)2(tmen)] (3), [ZnCl(flu)(neo)] (4), and [Zn(cyclam)(flu)2] (5), where py=pyridine, tmen=N,N,N',N'-Tetramethylethylene diamine, neo=2,9-Dimethyl-1,10-phenanthroline and cyclam=1,4,8,11-Tetraazacyclotetradecane. These complexes have been characterized by infrared spectroscopy, single-crystal X-ray structure analysis, elemental and thermal analysis. All complexes contain deprotonated flufenamic acid coordinated via carboxylato group to zinc atoms, but their structures differ in the carboxylato binding mode, the coordination number of the central atom, the shape of the coordination polyhedra and the resultant supramolecular structures. Furthermore, an interaction of complexes with calf-thymus DNA (CT DNA) and human serum albumin (HSA) has been investigated by spectroscopic techniques. Moreover, the complexes 1 and 2 inhibit the catalytic activity of topoisomerase I at 60μM.
- MeSH
- antiflogistika nesteroidní chemická syntéza chemie MeSH
- DNA-topoisomerasy I metabolismus MeSH
- DNA chemie MeSH
- inhibitory topoisomerasy I chemická syntéza chemie farmakologie MeSH
- komplexní sloučeniny chemická syntéza chemie farmakologie MeSH
- kyselina flufenamová chemická syntéza chemie MeSH
- lidé MeSH
- lidský sérový albumin chemie MeSH
- ligandy MeSH
- molekulární struktura MeSH
- skot MeSH
- zinek chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Diabetes is one of the most widespread diseases characterized by a deficiency in the production of insulin or its ineffectiveness. As a result, the increased concentrations of glucose in the blood lead not only to damage to many of the body's systems but also cause the nonenzymatic glycation of plasma proteins affecting their drug binding. Since the binding ability influences its pharmacokinetics and pharmacodynamics, this is a very important issue in the development of new drugs and personalized medicine. In this study, capillary electrophoresis-frontal analysis was used to evaluate the affinities between human serum albumin or its glycated form and the first generation of sulfonylurea antidiabetics, since their inadequate concentration may induce hypoglycaemia or on the contrary hyperglycaemia. The binding constants decrease in the sequence acetohexamide > tolbutamide > chlorpropamide > carbutamide both for normal and glycated human serum albumins, with glycated giving lower values. These results provide a more quantitative picture of how these drugs bind with normal and modified human serum albumin and indicate capillary electrophoresis-frontal analysis to be another tool for examining the changes arising from modifications of albumin, or any other protein, with all its benefits like short analysis time, small sample requirement, and automation.
