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1.
Food Chem ; 402: 134493, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36303387

RESUMO

The study explored the interaction mechanism between bovine serum albumin (BSA) and gamma-oryzanol (GO) by spectroscopic and computational approaches and the potential to enhance bioaccessibility and chemical stability of GO in the complex with BSA. Fluorescence spectroscopy showed that GO was bound to BSA with static quenching at a single binding site, being consistent with molecular docking results. Thermodynamic analysis and molecular dynamics simulation showed that electrostatic forces dominated interactions between BSA and GO. Besides, BSA-GO complex was more stable at pH 7.4 than at pH 2.0, with low root-mean-square deviation (2.57 Å vs 12.37 Å) and low binding energy (-424.23 kJ/mol at 277 K vs -188.55 kJ/mol at 277 K), but complex stability significantly decreased with increasing temperature. The bioaccessibility and stability of GO in the complex were significantly higher than those in water. This study provided theoretical support for developing proteins as delivery system for GO.


Assuntos
Soroalbumina Bovina , Soroalbumina Bovina/química , Simulação de Acoplamento Molecular , Sítios de Ligação , Espectrometria de Fluorescência , Termodinâmica , Ligação Proteica , Espectrofotometria Ultravioleta
2.
Sensors (Basel) ; 22(21)2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36365963

RESUMO

Based on ultraviolet absorption spectroscopy technology combined with stoichiometry, a portable photoelectric detection system with wireless transmission was designed with the advantages of simple operation, low cost, and quick response to realize the non-destructive detection of dihydrocoumarin content in coconut juice. Through the detection of a sample solution, the light intensity through the solution is measured and converted into absorbance. Particle swarm optimization (PSO) is applied to optimize support vector regression (SVR) to establish a corresponding concentration prediction model. At the same time, in order to solve the shortcomings of the conventional portable photoelectric detection equipment in data storage, data transmission, and other aspects, based on the optimal PSO-SVR model, we used Python language to develop a friendly graphical user interface (GUI), integrating data collection, storage, analysis, and prediction modeling in one, greatly simplifying the operation process. The experimental results show that, compared with the traditional methods, the system achieves the purpose of rapid and non-destructive detection and has a small gap compared with the detection results of the ultraviolet spectrophotometer. It provides a good method for the determination of dihydrocoumarin in coconut juice.


Assuntos
Algoritmos , Cocos , Espectrofotometria Ultravioleta , Luz
3.
Molecules ; 27(20)2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36296589

RESUMO

Advanced glycation end products (AGEs) are the compounds produced by non-enzymatic glycation of proteins, which are involved in diabetic-related complications. To investigate the potential anti-glycation activity of Myriocin (Myr), a fungal metabolite of Cordyceps, the effect of Myr on the formation of AGEs resulted from the glycation of bovine serum albumin (BSA) and the interaction between Myr and BSA were studied by multiple spectroscopic techniques and computational simulations. We found that Myr inhibited the formation of AGEs at the end stage of glycation reaction and exhibited strong anti-fibrillation activity. Spectroscopic analysis revealed that Myr quenched the fluorescence of BSA in a static process, with the possible formation of a complex (approximate molar ratio of 1:1). The binding between BSA and Myr mainly depended on van der Waals interaction, hydrophobic interactions and hydrogen bond. The synchronous fluorescence and UV-visible (UV-vis) spectra results indicated that the conformation of BSA altered in the presence of Myr. The fluorescent probe displacement experiments and molecular docking suggested that Myr primarily bound to binding site 1 (subdomain IIA) of BSA. These findings demonstrate that Myr is a potential anti-glycation agent and provide a theoretical basis for the further functional research of Myr in the prevention and treatment of AGEs-related diseases.


Assuntos
Produtos Finais de Glicação Avançada , Soroalbumina Bovina , Soroalbumina Bovina/química , Simulação de Acoplamento Molecular , Produtos Finais de Glicação Avançada/metabolismo , Corantes Fluorescentes , Sítios de Ligação , Espectrometria de Fluorescência , Termodinâmica , Ligação Proteica , Espectrofotometria Ultravioleta
4.
J Am Chem Soc ; 144(44): 20323-20331, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36301796

RESUMO

Thionyl chloride (Cl2SO) serves as a common Cl atom source in widespread applications of chlorine chemistry though little is known about the reactivity and spectroscopy of the ClSO radical after a Cl-S bond cleavage. We performed a Pulsed Laser Photolysis experiment to detect ClSO from Cl2SO photolysis at 248 nm in a gas-flow reactor by time-resolved UV-vis transient absorption spectroscopy. A few chemical tests, using I2 and NO2, suggested the structured absorption band between 260 and 320 nm belonged to ClSO radical and that the termolecular ClSO + Cl + M → Cl2SO association reaction occurred. From EOMIP-CCSD/ano-pVQZ calculations, the ClSO band was assigned to the 12A″ ← X2A″ transition involving the π* ← π transition of the SO bond and the vibrational progression to the SO stretching mode of the 12A″ state, with a maximum cross-section = (2.0 ± 0.5) × 10-18 cm2 near 286 nm (1σ uncertainty) and an average spacing of vibrational structure of 658 cm-1. The rapid decay of the ClSO signal monitored near 303 nm could be fit to a second-order kinetic model over 10-90 Torr, which yields an effective bimolecular rate coefficient kCl+ClSO = (1.48 ± 0.42) × 10-11 cm3 molecule-1 s-1 at 292 K and 90 Torr (1σ uncertainty). This fast recombination reaction suggests that Cl-containing SOx species might act as significant Cl atom reservoirs in sulfur oxide-rich environments such as Venus' atmosphere. Moreover, the reported UV spectrum provides a new means for monitoring the ClSO radicals.


Assuntos
Atmosfera , Cloro , Fotólise , Cinética , Atmosfera/química , Cloro/química , Espectrofotometria Ultravioleta
5.
Appl Opt ; 61(21): 6186-6192, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-36256231

RESUMO

A model combining UV-visible (UV-Vis) spectroscopy and support vector regression (SVR) for the quantitative detection of thiamethoxam in tea is proposed. First, each original UV-Vis spectrum in the sample set is decomposed into some intrinsic mode functions (IMFs) and a residual via ensemble empirical mode decomposition. Next, the decomposed IMFs are reconstructed into high-frequency and low-frequency matrices, and the residuals are combined into a trend matrix. Then, the SVR is used to build regression sub-models between each matrix and the content of thiamethoxam in tea. Finally, the combination model is established by a weighted average of the sub-models. The prediction results are compared with SVR and SVR coupled with several preprocessing methods, and the results demonstrate the superiority of the proposed approach in the quantitative detection of thiamethoxam in tea.


Assuntos
Chá , Tiametoxam , Espectrofotometria Ultravioleta , Chá/química
6.
Molecules ; 27(18)2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36144769

RESUMO

Theoretical investigations by density functional theory (DFT) and time-dependent DFT (TD-DFT) methods shed light on how the type of ligand or attached groups influence the electronic structure, absorption spectrum, electron excitation, and intramolecular and interfacial electron transfer of the Cu(II) complexes under study. The findings provide new insight into the designing and screening of high-performance dyes for dye-sensitized solar cells (DSSCs).


Assuntos
Energia Solar , Corantes/química , Cobre , Ligantes , Modelos Moleculares , Espectrofotometria Ultravioleta
7.
Molecules ; 27(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36144861

RESUMO

This study aims to experimentally and theoretically examine the plant Aethionema sancakense, which was determined as a new species and whose essential oil and fatty acid compositions were characterized by GC/GC-MS technique. Linoleic acid (23.1%), α-humulene (19.8%), camphene (13.9%), and heptanal (9.7%) were found to be the major essential oil components of A. sancakense aerial part structures. The quantum chemical calculations of these four molecules that are very important to this plant were performed using the density functional method (DFT)/B3LYP with the 6-31 G (d, p) basis set in the ground state for the gas phase. The molecular structures, HOMO-LUMO energies, electronic properties, Fukui functions, and molecular electrostatic potential (MEP) surfaces of the major constituents of Aethionema sancakense essential oil were calculated and interpreted. Finally, the RDG-NCI analysis of these molecules was performed to determine the non-covalent interactions present within the molecules.


Assuntos
Óleos Voláteis , Análise Espectral Raman , Monoterpenos Bicíclicos , Ácido Linoleico , Modelos Moleculares , Conformação Molecular , Teoria Quântica , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Termodinâmica , Vibração
8.
J Fluoresc ; 32(6): 2351-2362, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36171504

RESUMO

7-Hydroxycoumarin's FT-IR solid phase spectra were observed at 4000-400 cm-1. The spectra were analyzed in aspects of significant approaches. DFT was used to optimize the structure of the compound and its structural properties. The molecular properties were also determined by the HF/3-21G level. The bond lengths and bond angles were obtained by the computational study of the optimized geometry. The vibrational frequencies were determined in all these approaches, which were then matched to experimental frequencies, yielding an excellent agreement between measured and estimated frequency ranges. The UV-visible spectrum of 7HC was obtained and the electronic characteristics HOMO and LUMO energies were monitored by the time-dependent TD-DFT method. The spectral behavior of 7-Hydroxycoumarin was studied using fluorescence spectroscopy in a wide range of polar and non-polar solvents. Solvatochromic effect was observed in both the fluorescence and absorption spectra. The structural properties, energies, IR intensities, absorption wavelengths, and harmonic vibrational frequencies were compared with the obtainable experimental information of the molecule.


Assuntos
Teoria Quântica , Sais , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Modelos Moleculares , Espectrofotometria Ultravioleta , Solventes , Cumarínicos , Umbeliferonas , Termodinâmica
9.
J Chem Theory Comput ; 18(8): 4891-4902, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35913220

RESUMO

Predicting UV-visible absorption spectra is essential to understand photochemical processes and design energy materials. Quantum chemical methods can deliver accurate calculations of UV-visible absorption spectra, but they are computationally expensive, especially for large systems or when one computes line shapes from thermal averages. Here, we present an approach to predict UV-visible absorption spectra of solvated aromatic molecules by quantum chemistry (QC) and machine learning (ML). We show that a ML model, trained on the high-level QC calculation of the excitation energy of a set of aromatic molecules, can accurately predict the line shape of the lowest-energy UV-visible absorption band of several related molecules with less than 0.1 eV deviation with respect to reference experimental spectra. Applying linear decomposition analysis on the excitation energies, we unveil that our ML models probe vertical excitations of these aromatic molecules primarily by learning the atomic environment of their phenyl rings, which align with the physical origin of the π →π* electronic transition. Our study provides an effective workflow that combines ML with quantum chemical methods to accelerate the calculations of UV-visible absorption spectra for various molecular systems.


Assuntos
Aprendizado de Máquina , Espectrofotometria Ultravioleta
10.
Molecules ; 27(16)2022 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-36014381

RESUMO

A novel swarm intelligence algorithm, discretized grey wolf optimizer (GWO), was introduced as a variable selection tool in edible blend oil analysis for the first time. In the approach, positions of wolves were updated and then discretized by logical function. The performance of a wolf pack, the iteration number and the number of wolves were investigated. The partial least squares (PLS) method was used to establish and predict single oil contents in samples. To validate the method, 102 edible blend oil samples containing soybean oil, sunflower oil, peanut oil and sesame oil were measured by an ultraviolet-visible (UV-Vis) spectrophotometer. The results demonstrated that GWO-PLS models can provide best prediction accuracy with least variables compared with full-spectrum PLS, Monte Carlo uninformative variable elimination-PLS (MCUVE-PLS) and randomization test-PLS (RT-PLS). The determination coefficients (R2) of GWO-PLS were all above 0.95. Therefore, the research indicates the feasibility of using discretized GWO for variable selection in rapid determination of quaternary edible blend oil.


Assuntos
Algoritmos , Óleo de Soja , Análise dos Mínimos Quadrados , Óleo de Amendoim , Óleo de Soja/análise , Espectrofotometria Ultravioleta , Óleo de Girassol
11.
Environ Monit Assess ; 194(9): 630, 2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35920913

RESUMO

Water quality monitoring is very important in agricultural catchments. UV-Vis spectrometry is widely used in place of traditional analytical methods because it is cost effective and fast and there is no chemical waste. In recent years, artificial neural networks have been extensively studied and used in various areas. In this study, we plan to simplify water quality monitoring with UV-Vis spectrometry and artificial neural networks. Samples were collected and immediately taken back to a laboratory for analysis. The absorption spectra of the water sample were acquired within a wavelength range from 200 to 800 nm. Convolutional neural network (CNN) and partial least squares (PLS) methods are used to calculate water parameters and obtain accurate results. The experimental results of this study show that both PLS and CNN methods may obtain an accurate result: linear correlation coefficient (R2) between predicted value and true values of TOC concentrations is 0.927 with PLS model and 0.953 with CNN model, R2 between predicted value and true values of TSS concentrations is 0.827 with PLS model and 0.915 with CNN model. CNN method may obtain a better linear correlation coefficient (R2) even with small number of samples and can be used for online water quality monitoring combined with UV-Vis spectrometry in agricultural catchment.


Assuntos
Monitoramento Ambiental/métodos , Rios , Qualidade da Água , Agricultura/normas , Inglaterra , Análise dos Mínimos Quadrados , Redes Neurais de Computação , Espectrofotometria Ultravioleta/métodos
12.
Int J Biol Macromol ; 220: 415-425, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35985396

RESUMO

In this study, we have shown the interaction between opium poppy alkaloid noscapine-based ionic liquid [Pip-Nos]OTf and ct-DNA using UV-visible absorption spectroscopy, fluorescence spectroscopy, CD, and computational studies. The absorption spectra showed a hypochromic shift with no shift in the absorption maxima suggesting groove or electrostatic binding. Fluorescence spectra showed an enhancement in fluorescence emission suggesting that the probable mode of binding should be groove binding. Ethidium bromide (EB) competitive and Ionic strength study showed the absence of intercalative and electrostatic modes of interaction. Further, CD analysis of ct-DNA suggested a groove binding mode of interaction of [Pip-Nos]OTf with ct-DNA. [Pip-Nos]OTf displayed a strong binding with the target ct-DNA with a molecular docking score of -41.47 kJ/mol with all 3D coordinates and full conformation. Also, molecular binding contact analyses depicted the stable binding of drug and ct-DNA with potential hydrogen bonds and hydrophobic interactions. The structural superimposition dynamics analysis showed the stable binding of [Pip-Nos]OTf with the ct-DNA model through RMSD statistics. Moreover, the ligand interaction calculations revealed the involvement of large binding energy along with a high static number of molecular forces including the hydrogen bonds and hydrophobic interactions in their complexation. These significant results report the potency of [Pip-Nos]OTf and its important futuristic role in cancer therapeutics.


Assuntos
Líquidos Iônicos , Noscapina , Dicroísmo Circular , DNA/química , Etídio , Ligantes , Simulação de Acoplamento Molecular , Noscapina/farmacologia , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Termodinâmica
13.
Analyst ; 147(19): 4365-4370, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36043694

RESUMO

High-sensitivity trace oxygen sensing based on far-ultraviolet absorption spectroscopy was realized. The far-ultraviolet absorption spectrum of oxygen in the wavelength range of 170-200 nm at normal pressure was measured, and the maximum oscillation absorption peak occurred close to 180.18 nm. Through error analysis, the optimal wavelength range for accurate and sensitive oxygen measurements by ultraviolet absorption spectroscopy was identified as 180-189 nm. A total column (CL) calibration curve for oxygen was established, and the maximum optical path length (L1) of the system was determined to be 0.75(3) m by comparing the oxygen absorption with and without the sample cell. The oxygen detection sensitivity was 232 m-1, and the lowest detection limit was 12 ppm at the L1 optical path length. The highly sensitive trace oxygen sensing based on far-ultraviolet absorption spectroscopy exhibited significant potential for application with regard to nitrogen protection.


Assuntos
Luz , Oxigênio , Nitrogênio , Oxigênio/química , Espectrofotometria Ultravioleta/métodos
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 283: 121718, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-35963116

RESUMO

Spectroscopic behaviour of porphyrin is known to be sensitive to the choice of the solvent and has been used to probe solvation phenomena. The UV-visible spectra of N-confused tetraphenylporphyrin are observed in a series of binary solvent mixtures - (dichloromethane + diethyl ether), (dichloromethane + chlorobenzene) and (dichloromethane + ethyl acetate). The resulting ET scale for NCTPP solvation indicates nonlinear behaviour and preferential solvation by a solvent-solvent complex in all the three solvents - with the dichloromethane + ethyl acetate system showing the largest deviation from ideality. The data is fitted to the model based on solvent exchange equilibria for determining the preferential solvation parameters which are specific to the probe as well as the identity of solvents in the binary mixture. Further analysis using polarity parameters from literature indicate that the solvation of NCTPP in the (dichloromethane + ethyl acetate) mixture is dependent on the hydrogen bond accepting capacity and polarizability of the medium. Excess spectra derived from ATR-FTIR measurement of dichloromethane + ethyl acetate solutions lead to important inferences about the structure and role of solvent-solvent interactions responsible for the preferential solvation.


Assuntos
Cloreto de Metileno , Ligação de Hidrogênio , Solventes/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 283: 121728, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-35964350

RESUMO

In this study, seventeen flavonol derivatives (1-17) were evaluated with regard to their first- and second-order hyperpolarizability parameters. For this purpose, the molecular geometries of 1-17 were optimized by using B3LYP/6-311++G(d,p) level. Spectroscopic characterizations for 1-17 were executed through the calculations of IR, UV-vis, 1H NMR and 13C NMR spectra. The quantum chemical parameters such as electronegativity, chemical hardness, chemical potential and electrophilicity indexes were obtained by using the frontier molecular orbital (FMO) energies. The potential energy distribution (PED) analysis was used to provide a detailed assignment of vibrational bands. Important contributions to electronic absorption bands from FMOs were also evaluated. The distribution of FMOs to the whole molecule was investigated to determine the nature of electronic charge transfers in 1-17. The static and dynamic first- and second-order hyperpolarizability parameters for 1-17 were calculated by using B3LYP/6-311++G(d,p) level. The static ß and γ were calculated at the ranges of 9.8279-0.0303 × 10-29 esu and 80.200-268.40 × 10-36 esu. The dynamic ß and γ (ω = 532 nm) were also obtained in the field of 1.0440-71.786 × 10-29 esu and 306.20-3607.00 × 10-36 esu. This wide range of ß and γ values indicate that flavonol derivatives with rational substitution may be promising candidates for first- and second-order NLO applications.


Assuntos
Flavonóis , Vibração , Teoria da Densidade Funcional , Modelos Moleculares , Conformação Molecular , Teoria Quântica , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Eletricidade Estática , Termodinâmica
16.
Anal Chem ; 94(35): 12152-12158, 2022 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-35994566

RESUMO

UV-vis spectroelectrochemistry is assessed as a tool for the diagnosis and quantitative in situ investigation of the incidence of comproportionation in multielectron transfer processes. Thus, the sensitivity of the limiting current chronoabsorptometric signals related to the different redox states to the comproportionation kinetics is studied theoretically for different working modes (normal and parallel light beam arrangements) and mass transport regimes (from semi-infinite to thin layer diffusion). The theoretical results are applied to the spectroelectrochemical study of the two-electron reduction of the anthraquinone-2-sulfonate in alkaline aqueous solution, tuning the thermodynamic favorability of the comproportionation reaction through the electrolyte cation. The quantitative analysis of the experimental results reveals the occurrence of comproportionation in the three media examined, showing different kinetics depending on the cationic species in solution.


Assuntos
Antraquinonas , Elétrons , Cinética , Oxirredução , Espectrofotometria Ultravioleta/métodos
17.
Eur J Pharm Sci ; 179: 106276, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-35977652

RESUMO

Certain ruthenium compounds are found to be potent growth inhibitors for cancer cells. In the current study, a novel ruthenium-triphenylphosphine (PPh3) cation and silver-2-mercapto nicotinate acid (H2mna) anion complex (RSC) was synthesized, and its molecular structure was determined by IR, NMR and X-ray crystallography. Biological assays revealed that RSC strongly inhibited the viability of MCF-7 and MDA-MB-231 cells with IC50 values of 9.6±1.1 and 7.5±0.8 µM, respectively, and significantly blocked their migration rates. Ultraviolet spectroscopy and fluorescence emission experiments demonstrated that RSC interacted with BSA, but not DNA. Further studies on [Ag6(Hmna)2(mna)4]4- binding with BSA and DNA found the anion did not interact with these biomolecules, indicating that RSC exerted its biological functions through its ruthenium-PPh3 complex (RTC) moiety, and molecular docking provided additional evidence supporting this result. Fluorescence resonance energy transfer showed that the number of binding sites (n) and binding constant of RTC-BSA complex were 1 and 8.60 × 104 M-1 at 310K, suggesting a strong interaction between RTC and BSA. The thermodynamic parameters ΔG0, ΔH0 and ΔS0 of the binding were calculated, and it was demonstrated that the binding of RTC with BSA was enthalpy-driven, and the main forces between RTC and BSA were electrostatic force and hydrogen bonding. Molecular docking showed that the binding site of BSA with RSC was located on the interface between the domains IIA and IIB of the protein. The present study sheds light on that a ruthenium mono-coordinated with PPh3 complex could help to design and develop a new class of antitumor drugs.


Assuntos
Antineoplásicos , Rutênio , Simulação de Acoplamento Molecular , Prata , Soroalbumina Bovina/química , Sítios de Ligação , Antineoplásicos/farmacologia , Antineoplásicos/química , Termodinâmica , DNA , Ligação Proteica , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
18.
J Proteome Res ; 21(10): 2493-2503, 2022 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-36043517

RESUMO

The direct correlation between proteoforms and biological phenotype necessitates the exploration of mass spectrometry (MS)-based methods more suitable for proteoform detection and characterization. Here, we couple nano-hydrophobic interaction chromatography (nano-HIC) to ultraviolet photodissociation MS (UVPD-MS) for separation and characterization of intact proteins and proteoforms. High linearity, sensitivity, and sequence coverage are obtained with this method for a variety of proteins. Investigation of collisional cross sections of intact proteins during nano-HIC indicates semifolded conformations in low charge states, enabling a different dimension of separation in comparison to traditional, fully denaturing reversed-phase separations. This method is demonstrated for a mixture of intact proteins from Escherichia coli ribosomes; high sequence coverage is obtained for a variety of modified and unmodified proteoforms.


Assuntos
Proteínas , Espectrometria de Massas em Tandem , Cromatografia Líquida/métodos , Escherichia coli/genética , Interações Hidrofóbicas e Hidrofílicas , Espectrofotometria Ultravioleta/métodos , Espectrometria de Massas em Tandem/métodos , Raios Ultravioleta
19.
Sci Rep ; 12(1): 14723, 2022 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-36042232

RESUMO

Studying the binding interaction between biological macromolecules and small molecules has formed the core of different research aspects. The interaction of palbociclib with calf thymus DNA at simulated physiological conditions (pH 7.4) was studied using different approaches, including spectrophotometry, spectrofluorimetry, FT-IR spectroscopy, viscosity measurements, ionic strength measurements, thermodynamic, molecular dynamic simulation, and docking studies. The obtained findings showed an apparent binding interaction between palbociclib and calf thymus DNA. Groove binding mode was confirmed from the findings of competitive binding studies with ethidium bromide or rhodamine B, UV-Vis spectrophotometry, and viscosity assessment. The binding constant (Kb) at 298 K calculated from the Benesi-Hildebrand equation was found to be 6.42 × 103 M-1. The enthalpy and entropy changes (∆H0 and ∆S0) were - 33.09 kJ mol-1 and 61.78 J mol-1 K-1, respectively, showing that hydrophobic and hydrogen bonds constitute the primary binding forces. As indicated by the molecular docking results, palbociclib fits into the AT-rich region of the B-DNA minor groove with four base pairs long binding site. The dynamic performance and stability of the formed complex were also evaluated using molecular dynamic simulation studies. The in vitro study of the intermolecular binding interaction of palbociclib with calf thymus DNA could guide future clinical and pharmacological studies for the rational drug scheming with enhanced or more selective activity and greater efficacy.


Assuntos
Simulação de Dinâmica Molecular , Sítios de Ligação , Dicroísmo Circular , DNA , Simulação de Acoplamento Molecular , Piperazinas , Piridinas , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica , Viscosidade
20.
Int J Biol Macromol ; 217: 1027-1036, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-35907469

RESUMO

Drugs, in general, exhibit their pharmacological activity in binding with intracellular targets. Numerous anticancer and antibacterial drugs target DNA as one of their primary intracellular targets. Dexlansoprazole (DLP) is a heterocyclic compound containing benzimidazole moiety and a proton pump inhibitor used to treat gastroesophageal reflux disease. The interaction of dexlansoprazole with calf thymus DNA (ct-DNA) has been studied using biophysical methods. The UV-Visible studies revealed a binding constant of 2.15 ± 0.3 × 104 M-1 which is close to the value of 2.44 ± 0.3 × 104 M-1 obtained from the fluorescence studies. Competitive displacement studies using the fluorescence spectroscopic method with ethidium bromide and Hoechst as DNA markers suggested the groove binding mode of DLP in ct-DNA. The groove binding mode of DLP in ct-DNA was complemented by the results of viscosity and DNA melting studies. Further studies on the effect of ionic strength and potassium iodide on DLP binding with ct-DNA supported the observed binding mode. Circular dichroism studies reflected no significant conformational variation in ct-DNA after the interaction. The binding mode obtained from the experimental studies was corroborated by the molecular docking studies that showed the position of DLP in the minor groove of ct-DNA along with the receptor interface restudies involved in the interaction.


Assuntos
DNA , Dicroísmo Circular , DNA/química , Dexlansoprazol , Simulação de Acoplamento Molecular , Conformação de Ácido Nucleico , Desnaturação de Ácido Nucleico , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Termodinâmica , Viscosidade
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