UV-Vis quantification of the iron content in iteratively steam and HCl purified single-walled carbon nanotubes.

As-produced carbon nanotubes contain impurities which can dominate the properties of the material and are thus undesired. Herein we present a multi-step purification treatment that combines the use of steam and hydrochloric acid in an iterative manner. This allows the reduction of the iron content down to 0.2 wt. % in samples of single-walled carbon nanotubes (SWCNTs). Remarkably, Raman spectroscopy analysis reveals that this purification strategy does not introduce structural defects into the SWCNTs' backbone. To complete the study, we also report on a simplified approach for the quantitative assessment of iron using UV-Vis spectroscopy. The amount of metal in SWCNTs is assessed by dissolving in HCl the residue obtained after the complete combustion of the sample. This leads to the creation of hexaaquairon(III) chloride which allows the determination of the amount of iron, from the catalyst, by UV-Vis spectroscopy. The main advantage of the proposed strategy is that it does not require the use of additional complexing agents.

Complexes of Gold(III) with Hydrazones Derived from Pyridoxal: Stability, Structure, and Nature of UV-Vis Spectra.

Pyridoxal and pyridoxal 5'-phosphate are aldehyde forms of B6 vitamin that can easily be transformed into each other in the living organism. The presence of a phosphate group, however, provides the related compounds (e.g., hydrazones) with better solubility in water. In addition, the phosphate group may sometimes act as a binding center for metal ions. In particular, a phosphate group can be a strong ligand for a gold(III) ion, which is of interest for researchers for the anti-tumor and antimicrobial potential of gold(III). This paper aims to answer whether the phosphate group is involved in the complex formation between gold(III) and hydrazones derived from pyridoxal 5'-phosphate. The answer is negative, since the comparison of the stability constants determined for the gold(III) complexes with pyridoxal- and pyridoxal 5'-phosphate-derived hydrazones showed a negligible difference. In addition, quantum chemical calculations confirmed that the preferential coordination of two series of phosphorylated and non-phosphorylated hydrazones to gold(III) ion is similar. The preferential protonation modes for the gold(III) complexes were also determined using experimental and calculated data.

Fast, sensitive LC-MS resolution of α -hydroxy acid biomarkers via SPP-teicoplanin and an alternative UV detection approach.

Enantioseparation of α -hydroxy acids is essential since specific enantiomers of these compounds can be used as disease biomarkers for diagnosis and prognosis of cancer, brain diseases, kidney diseases, diabetes, etc., as well as in the food industry to ensure quality. HPLC methods were developed for the enantioselective separation of 11 α -hydroxy acids using a superficially porous particle-based teicoplanin (TeicoShell) chiral stationary phase. The retention behaviors observed for the hydroxy acids were HILIC, reversed phase, and ion-exclusion. While both mass spectrometry and UV spectroscopy detection methods could be used, specific mobile phases containing ammonium formate and potassium dihydrogen phosphate, respectively, were necessary with each approach. The LC-MS mode was approximately two orders of magnitude more sensitive than UV detection. Mobile phase acidity and ionic strength significantly affected enantioresolution and enantioselectivity. Interestingly, higher ionic strength resulted in increased retention and enantioresolution. It was noticed that for formate-containing mobile phases, using acetonitrile as the organic modifier usually resulted in greater enantioresolution compared to methanol. However, sometimes using acetonitrile with high ammonium formate concentrations led to lengthy retention times which could be avoided by using methanol as the organic modifier. Additionally, the enantiomeric purities of single enantiomer standards were determined and it was shown that almost all standards contained some levels of enantiomeric impurities.

Highly sensitive biofunctionalized nanostructures for paper-based colorimetric sensing of hydrogen peroxide in raw milk.

Hydrogen Peroxide (H2O2) is a highly hazardous, toxic, and carcinogenic chemical compound utilised in various industries-based applications. Despite strict restriction, they are deliberately added to food items such as milk as preservatives to increase its shelf life. Herein, we have formulated a green rapid colorimetric nanosensor for detection of H2O2 in milk using cotton leaves as both reducing and functionalizing agent for synthesis of silver nanoparticles (AgNPs). UV-Vis spectra exhibit a strong plasmonic peak at around 434 nm. X-Ray Diffraction (XRD) analysis was performed to determine the crystallinity of the nanoparticles. Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM) characterizations revealed spherical morphology with size approximately âˆ¼16 nm. This functionalized nanoparticle could colorimetrically sense presence of H2O2 in milk samples both in liquid media and on paper substrates with Limit of Detection (LOD) of 8.46 ppm even in presence of other interfering substances in milk. This inexpensive route will pave the way for in depth research.

Exploring the interaction of biologically active compounds with DNA through the application of the SwitchSense technique, UV-Vis spectroscopy, and computational methods.

DNA is a key target for anticancer and antimicrobial drugs. Assessing the bioactivity of compounds involves in silico and instrumental studies to determine their affinity for biomolecules like DNA. This study explores the potential of the switchSense technique in rapidly evaluating compound bioactivity towards DNA. By combining switchSense with computational methods and UV-Vis spectrophotometry, various bioactive compounds' interactions with DNA were analyzed. The objects of the study were: netropsin (as a model compound that binds in the helical groove), as well as derivatives of pyrazine (PTCA), sulfonamide (NbutylS), and anthraquinone (AQ-NetOH). Though no direct correlation was found between switchSense kinetics and binding modes, this research suggests the technique's broader utility in assessing new compounds' interactions with DNA. used as analytes whose interactions with DNA have not been yet fully described in the literature.

DFT study of the spectroscopic behaviour of different iron(II)-terpyridine derivatives with application in DSSCs.

Through a comprehensive computational analysis utilizing Density Functional Theory (DFT), we clarify the electronic structure and spectroscopic properties of modified iron(II)-terpyridine derivatives, with the aim of enhancing the efficiency of Dye-Sensitized Solar Cells (DSSCs). We optimized a series of nineteen iron(II)-terpyridine derivatives and related compounds in acetonitrile (MeCN) as the solvent using TDDFT, evaluating their potential as dyes for DSSCs. From the conducted computations on the optimized geometries of the nineteen [Fe(Ln)2]2+ complexes, containing substituted terpyridine and related ligands L1-L19, we determined the wavelengths (λ in nm), transition energy (E in eV), oscillator strength (f), type of transitions, excited state lifetime (τ), light harvesting efficiency (LHE), frontier orbital character and their energies (ELUMO/EHOMO), natural transition orbitals (NTOs), injection driving force of a dye (ΔGinject), and regeneration driving force of a dye (ΔGregenerate). Results show that the theoretically calculated values for assessing dye efficiency in a DSSC correlate with available experimental values. The UV-visible spectra of [Fe(Ln)2]2+ exhibited a peak above 500 nm (λmax) in the visible region, attributed to the ligand-to-metal charge transfer band (LMCT) in literature, and a significant absorbance peak at approximately 300 nm (λA,max) in the UV region. The M06-D3/CEP-121G method replicated all reported λmax and λA,max values with a mean absolute deviation (MAD) of 21 and 18 nm, respectively. Our findings underscore the connections between electronic modifications and absorption spectra, emphasizing their impact on the light-harvesting capabilities and overall performance of DSSCs. This research contributes to the advancement of fundamental principles governing the design and optimization of novel photovoltaic materials, facilitating the development of more efficient and sustainable solar energy technologies.

Spectroscopic, computational, cytotoxicity, and docking studies of 6-bromobenzimidazole as anti-breast cancer agent.

6-Bromobenzimidazole (6BBZ) has been calculated in this study utilizing the 6-311++G(d,p) basis set and the Becke-3-Lee-Yang-Parr density functional approaches. The basic frequencies and geometric optimization are known. FTIR, FT-Raman, and UV-Vis spectra of the substance are compared between its computed and observed values. The energy gap between highest occupied molecular orbital-lowest unoccupied molecular orbital and molecule electrostatic potentials has been represented by charge density distributions that may be associated with the biological response. Time-dependent density functional theory calculations in the gas phase and dimethyl sulfoxide were carried out to ascertain the electronic properties and energy gap values using the same basis set. Molecular orbital contributions are investigated using the overlap population, partial, and total densities of states. Natural bond analysis was found to have strong electron delocalization by means of π(C4-C9) → π*(C5-C6), LP (N1) → π*(C7-C8), and LP(Br12) → π*(C5-C6) interactions. The Fukui function and Mulliken analysis have been explored on the atomic charges of the molecule. The nuclear magnetic resonance chemical shifts for 1 H and 13 C have been computed using the gauge-independent atomic orbital technique. With the highest binding affinity (-6.2 kcal mol-1 ) against estrogen sulfotransferase receptor (PDB ID: 1AQU) and low IC50 value of 17.23 µg/mL, 6BBZ demonstrated potent action against the MCF-7 breast cancer cell line. Studies on the antibacterial activity and ADMET prediction of the molecule have also been carried out.

Elucidation of binding mechanism of rhodanine derivative P4OC on bovine serum albumin.

Rhodanine is an important scaffold in medicinal chemistry and it act as potent anticancer agent and other pharmacological effects. In pharmacokinetics and pharmacodynamics studies of the drug, the drug binding properties on serum protein is crucial for producing better drug. This study was designed to explore the binding interactions between the Rhodanine derivative (P4OC) on Bovine Serum Albumin (BSA). The interactions between P4OC and BSA were investigated using biophysical approach and molecular docking. The quenching mechanism and binding constants of P4OC on BSA were determined by biophysical approach through fluorescence spectroscopic experiments. Circular dichroism (CD) spectroscopy was used to study the secondary structural changes of BSA upon P4OC binding. The fluorescence experiments of P4OC binding on BSA show good drug binding with static quenching constants using stern Volmer plot and found the quenching constant value KP4OC = 1.12762 × 1013 M-1 with corresponding binding free energy (ΔG) -2.303 kcal/mol. The molecular displacement fluorescence emission on BSA-P4OC complex by site specific markers shows that P4OC binds at I A sub-domain of BSA further confirmed peak shift by synchronous fluorescence of P4OC on BSA with tyrosine, tryptophan and phenylalanine amino acids. Increasing concentration of P4OC on BSA found secondary structural changes, the percentage of α-helix was decreased as well increase percentage of ß-sheet and random coil. The binding of P4OC to BSA was computationally studied by molecular docking methods. Thus, results obtained are in excellent agreement with experimental and theoretical results with respect to the binding mechanism and binding constant of P4OC on BSA. We concluded that, the rhodanine derivative P4OC possesses good drug binding properties on BSA. Further P4OC may be evaluated its potential pharmacological activities on clinical trial.Communicated by Ramaswamy H. Sarma.

Comprehending the intermolecular interaction of dacomitinib with bovine serum albumin: experimental and theoretical approaches.

Dacomitinib (DAC), as a member of tyrosine kinase inhibitors is primarily used to treat non-small cell lung cancer. The intermolecular interaction between DAC and bovine serum albumin (BSA) was comprehended with the help of experiments and theoretical simulations. The outcomes indicated that DAC quenched the endogenous fluorescence of BSA through static quenching mode. In the binding process, DAC was preferentially inserted into the hydrophobic cavity of BSA subdomain IA (site III), and a fluorescence-free DAC-BSA complex with molar ratio of 1:1 was generated. The outcomes confirmed that DAC had a stronger affinity on BSA and the non-radiative energy transfer occurred in the combination process of two. And, it can be inferred from the outcomes of thermodynamic parameters and competition experiments with 8-aniline-1-naphthalenesulfonic acid (ANS) and D-(+)- sucrose that hydrogen bonds (H-bonds), van der Waals forces (vdW) and hydrophobic forces had a significant impact in inserting DAC into the hydrophobic cavity of BSA. The outcomes from multi-spectroscopic measurements that DAC could affect the secondary structure of BSA, that was, α-helix content decreased slightly from 51.0% to 49.7%. Moreover, the combination of DAC and BSA led to a reduction in the hydrophobicity of the microenvironment around tyrosine (Tyr) residues in BSA while had little influence on the microenvironment of around tryptophan (Trp) residues. The outcomes from molecular docking and molecular dynamics (MD) simulation further demonstrated the insertion of DAC into site III of BSA and hydrogen energy and van der Waals energy were the dominant energy of DAC-BSA stability. In addition, the influence of metal ions (Fe3+, Cu2+, Co2+, etc.) on the affinity of the system was explored.Communicated by Ramaswamy H. Sarma.

Intercalation of anticancer drug Palbociclib with calf-thymus DNA: new insights from molecular spectroscopic, molecular dynamic simulations and cleavage studies.

The interaction between the anti-cancer drug Palbociclib (PAL) and calf-thymus DNA (CT-DNA) was investigated using various biophysical techniques in a physiological buffer (pH 7.4). It was found that PAL intercalated into the base pairs of CT-DNA as evidenced from the results of UV-Vis, fluorescence, circular dichroism (CD), competitive binding assay with ethidium bromide (EB) and Hoechst 33258, KI quenching study, the effect of denaturing agent and viscosity measurements. The magnitude of binding constants (106 M-1) at different temperatures suggested strong binding between PAL and CT-DNA during complexation. The observed ΔHo > 0 and ΔSo > 0 indicated that the binding process is primarily driven by hydrophobic interactions. Molecular docking studies indicated partial intercalation of pyridopyrimidine ring between the base pairs of DNA. Free energy surface (FES) analysis derived from metadynamics simulation studies revealed the PAL-induced cleavage of DNA, which was confirmed by gel electrophoresis experiments.Communicated by Ramaswamy H. Sarma.

Inflammatory Studies of Dehydroandrographolide: Isolation, Spectroscopy, Biological Activity, and Theoretical Modeling.

Dehydroandrographolide (DA) was isolated and experimentally characterized utilizing FT-IR, UV-Vis, and NMR spectroscopy techniques along with detailed theoretical modelled at the DFT/B3LYP-D3BJ/6-311 + + G(d,p) level of theory. Substantially, molecular electronic property investigations in the gaseous phase alongside five different solvents (ethanol, methanol, water, acetonitrile and DMSO) were comprehensively reported and compared with the experimental results. The globally harmonized scale (GHS), which is used to identify and label chemicals, was also utilized to demonstrate that the lead compound predicted an LD50 of 1190 mg/kg. This finding implies that consumers can safely consume the lead molecule. Notable impacts on hepatotoxicity, cytotoxicity, mutagenicity, and carcinogenicity were likewise found to be minimal to nonexistent for the compound. Additionally, in order to account for the biological performance of the studied compound, in-silico molecular docking simulation analysis was examined against different anti-inflammatory target of enzymes (3PGH, 4COX, and 6COX). From the examination, it can be inferred that DA@3PGH, DA@4COX, and DA@6COX, respectively, showed significant negative binding affinities of -7.2 kcal/mol, -8.0 kcal/mol, and - 6.9 kcal/mol. Thus, the high mean binding affinity in contrast to conventional drugs further reinforces these results as an anti-inflammatory agent.

Exploring the interaction of tepotinib with calf thymus DNA using molecular dynamics simulation and multispectroscopic techniques.

In recent times, there has been a surge in the discovery of drugs that directly interact with DNA, influencing gene expression. As a result, understanding how biomolecules interact with DNA has become a major area of research. One such drug is Tepotinib (TPT), an FDA-approved anti-cancer medication known as a MET tyrosine kinase inhibitor, used in chemotherapy for metastatic non-small cell lung cancer (NSCLC) with MET exon 14 skipping alterations. In our study, we adopted both biophysical and in-silico methods to investigate the binding relationship of TPT and ctDNA. The absorption spectra of ctDNA exhibited a hypochromic effect when titrated with TPT and the binding constant of TPT-ctDNA complex was calculated, Ka = 9.91 × 104 M-1. By computing bimolecular enhancement constant (KB) and thermodynamic enhancement constant (KD) in fluorometric investigations, it was found that the fluorescence enhancement is a result of a static process involving the ctDNA-TPT complex formation in the ground state, as opposed to a dynamic process. The displacement assay results further supported this finding, showing that TPT exhibits a binding preference for minor groove of ct-DNA and was also demonstrated by KI quenching and CD spectroscopy. The molecular docking and molecular dynamic simulations validated TPT's groove binding nature and binding pattern with ctDNA, respectively. Thus, the results of our present investigation offer valuable insights into the interaction between TPT and ctDNA. It is evident that TPT, as an anti-cancer medication, binds to the minor groove of ctDNA.

A novel imidazole-based azo molecule: synthesis, characterization, quantum chemical calculations, molecular docking, molecular dynamics simulations and ADMET properties.

CONTEXT: Today, the treatment or prevention of cancer, which is one of the most important causes of death, has a very important place. On the other hand, the discovery of new antimicrobial agents is also important because of antibiotic resistance that can occur in humans. For these reasons, in this study, the synthesis, quantum chemical calculations, and in silico studies of a novel azo molecule with high bioactive potential were carried out. In the first step of the synthesis part, (3-(4-methyl-1H-imidazol-1-yl)-5-(trifluoromethyl)aniline compound, which is the raw material of the drug used in cancer treatments, was synthesized. In the second step, a novel product 2-hydroxy-5-((3-(4-methyl-1H-imidazol-1-yl)-5-trifluoromethyl)phenyl)diazenyl)benzaldehyde (HTB) was obtained as a result of the reaction of salicylaldehyde coupling to this compound. Then, as it was being spectroscopically described, its geometry was optimized. In order to perform quantum chemical calculations, the molecular structure, vibrational spectroscopic data, electronic transition absorption wavelengths, HOMO and LUMO analyses, molecular electrostatic potential (MEP) and potential energy surface (PES) of the molecule were all taken into consideration. Using molecular docking simulations, in silico interactions of the HTB molecule with some anticancer and antibacterial-related proteins were studied. In addition, the ADMET parameters of the HTB were also predicted. METHODS: The structure of the synthesized compound was elucidated using 1H-NMR, 13C-NMR (APT), 19F-NMR, FT-IR and UV-vis spectroscopic methods. The optimized geometry, molecular electrostatic potential diagram and vibrational frequencies of the HTB molecule were calculated at the DFT/B3LYP/6-311G(d,p) level. The TD-DFT method was used to calculate HOMOs-LUMOs and electronic transitions, and the GIAO method was used to calculate chemical shift values. It was observed that the experimental spectral data were in good agreement with the theoretical ones. Molecular docking simulations of the HTB molecule using 4 different proteins were investigated. Two of these proteins were involved in simulating anticancer activity and the other two in simulating antibacterial activity. According to molecular docking studies, the binding energies of the complexes formed by the HTB compound with the 4 selected proteins were between -9.6 and -8.7 kcal/mol. HTB showed the best affinity with VEGFR2 protein (PDB ID: 2XIR) and the binding energy of this interaction was found to be -9.6 kcal/mol. The HTB-2XIR interaction was examined with molecular dynamics simulation for 25 ns and it was determined that this complex was stable during this time. In addition, the ADMET parameters of the HTB were also calculated, and from these values, it was determined that the compound has very low toxicity and high oral bioavailability.

Spectroscopic investigations, quantum chemical, drug likeness and molecular docking studies of methyl 1-methyl-4-nitro-pyrrole-2-carboxylate: A novel ovarian cancer drug.

Density functional theory (DFT) calculation was used to analyse the structural and vibrational properties of Methyl 1-Methyl-4-nitro-pyrrole-2-carboxylate (MMNPC) using the cc-pVTZ basis set. The potential energy surface scan and the most stable molecular structure were optimized using Gaussian 09 program. A potential energy distribution calculation was used to calculate and assign vibrational frequencies using the VEDA 4.0 program package. The Frontier Molecular Orbitals (FMOs) were analysed to determine their related molecular properties. Ab initio density functional theory (B3LYP/cc-pVTZ) method with basis set was used to calculate 13C NMR chemical shift values of MMNPC in the ground state. Fukui function and molecular electrostatic potential (MEP) analysis confirmed the bioactivity of the MMNPC molecule. The charge delocalization and stability of the title compound were studied using natural bond orbital analysis. All experimental spectral values from FT-IR, FT-Raman, UV-VIS, and 13C NMR are in good agreement with the value calculated by the DFT. Molecular docking analysis was carried out to find the MMNPC compound that can be used as a potential drug development candidate for ovarian cancer.

Catechol derivatives interact with bovine serum albumin: Correlation of non-covalent interactions and antioxidant activity.

The interactions of catechol derivatives with model transportation protein-bovine serum albumin (BSA) were deciphered by the multispectral techniques, molecular docking and multifunctional wavefunction (Multiwfn). The representative catechol derivatives caffeic acid (CA) and 1-monocaffeoyl glycerol (1-MCG) with an (E)-but-2-enoic acid and a 2,3-dihydroxypropyl(E)-but-2-enoate side chain, respectively, were chosen in present study. The interaction results revealed the extra non-polar interactions and abundant binding sites facilitate the easier and stronger binding of 1-MCG-BSA. The α-helix content of BSA decreased and the hydrophilicity around Tyr and Trp changed due to the different interaction between catechol and BSA. The H2O2-damaged RAW 264.7, HaCat and SH-SY5Y were applied to investigate the anti-ROS properties of the catechol-BSA complexes. The results illuminated that the 2,3-dihydroxypropyl(E)-but-2-enoate side chain of 1-MCG facilitated the preferable biocompatibility and antioxidant property of its binding complex. These results revealed that the interaction of catechol-BSA binding complexes could influence their biocompatibility and antioxidant properties.

Theoretical and experimental spectroscopic studies and analysis for wave function on N-phenylmorpholine-4-carboxamide benzene-1,2-diamine with computational techniques.

The present study focuses on structural and chemical analyses of N-phenylmorpholine-4-carboxamide benzene-1,2-diamine (PMCBD) using quantum computational methods. The calculated bond angle, length, and dihedral angle between atoms were compared with measured values. The observed and stimulated FT-IR (Fourier Transform Infrared Spectroscopy) spectra parameters for vibrational wavenumbers and their associated PED (Potential Energy Distribution) values in percentage have been obtained from VEDA4 software. The electronic transitions of PMCBD were discussed by TD-SCF/DFT/B3LYP based on the 6-311++G(d,p) basis set with solvents such as chloroform, ethanol, and dimethyl sulfoxide (DMSO) and gas. Density functional computations were used to study the band energy between HOMO and LUMO using the B3LYP/6-311++G(d,p) level. Mulliken analysis and natural population analysis were used for a better understanding of charge levels on different atoms such as N, H and O. The natural bonding orbital (NBO) analysis proved helpful in studying molecular and bond strengths. (NBO). The ESP acquired data on the molecule's size, shape, charge density distribution, and chemical reactivity site. This was done by mapping electron density on the surface with electrostatic potential. Non-linear optical detection of PMCBD was also discussed. Aside from the electron localization function map, state densities are also mapped using Multiwfn software, a wave function analyzer.

Molecular dynamics investigation, Hirshfeld surface analysis, and molecular docking studies by quantum chemical evaluation of new novel NLO 5-hydroxy-3,6,7,8-tetramethoxyflavone.

CONTEXT: The molecular structure of the compound, spectroscopic investigations (FT-IR, FT-Raman, and NMR), and the frontier energy level analysis of 5-hydroxy-3,6,7,8-tetramethoxyflavone (5HTMF) were all examined using density functional theory (DFT) methods. Comparisons were made between predicted DFT theoretical vibrational wavenumbers and observed data. The chemical reactivity of 5HTMF was studied using DFT/PBEPBE approach that included frontier orbital energies, optical characteristics, and chemical descriptors. All our theoretical calculations have been done using the Gaussian 09W package. METHODS: The cytotoxic activity of the bioactive ligand was checked against human cancer cell lines A549 and MCF-7 in vitro by the MTT assay. Hence, the docking and in vitro activity against cancer cell lines display positive results. The present ligand performance appears to be a promising way for anticancer agents with better efficacy. A molecular docking study of 5HTMF drug against Bcl-2 protein structures was performed by using the open-source AutoDock 4.2 and AutoDock Vina tools program packages.

In vitro interactions of two pesticides, propazine and quinoxyfen with bovine serum albumin: Spectrofluorometric and molecular docking investigations.

Binding mechanisms of two selected pesticides, propazine (PRO) and quinoxyfen (QUI) with bovine serum albumin (BSA) was examined using fluorescence, absorption and molecular docking methods. Intrinsic fluorescence of BSA was quenched in the presence of both PRO and QUI. The quenching was ascertained to be conversely linked to temperature, which suggested the contribution of static quenching process in the PRO-BSA and QUI-BSA complex formations. This results were validated by the enhancement in absorption spectrum of BSA upon binding with PRO and QUI. Binding constant values (Kf = 9.55-0.60 × 10-3 M-1 for PRO-BSA system; Kf = 7.08-5.01 × 102 M-1 for QUI-BSA system) and number of binding site (n) values for the PRO-BSA and QUI-BSA systems at different temperatures affirmed a weak binding strength with a set of equivalent binding sites on BSA. Thermodynamic data obtained for both the PRO-BSA and QUI-BSA interactions predicted that the association process was spontaneous and non-covalent contacts such as hydrophobic interactions, van der Waals forces and hydrogen bonds participated in the binding reactions. This result was further supported by the molecular docking assessments. Three-dimensional spectral results revealed the microenvironmental alterations near tryptophan (Trp) and tyrosine (Tyr) residues in BSA by the addition of PRO and QUI. The docking analysis demonstrated the binding pattern for the PRO-BSA and QUI-BSA systems and disclosed the preferred binding site of both PRO and QUI as site I (subdomain IIA) of BSA.

Structural Insight into Groove Binding of Yohimbine with Calf Thymus DNA: A Spectroscopic, Calorimetric, and Computational Approach.

A variety of anticancer and antibacterial drugs target DNA as one of their primary intracellular targets. Understanding ligand-DNA interactions and developing new, promising bioactive molecules for clinical use are greatly aided by elucidating the interaction between small molecules and natural polymeric DNAs. Small molecules' ability to attach to and inhibit DNA replication and transcription provides more information on how drugs impact the expression of genes. Yohimbine has been broadly studied in pharmacological properties, while its binding mode to DNA has not been explicated so far. In this study, an attempt was made to explore the interaction between Yohimbine (YH) and calf thymus (CT-DNA) by using varying thermodynamics and in silico approaches. Minor hypochromic and bathochromic shifts of fluorescence intensity were observed, suggesting the binding of YH to CT-DNA. The Scatchard plot analysis using the McGhee-von Hipple method revealed noncooperative binding and affinities in the range of 105 M-1. The binding stoichiometry value is 2:1 (2 molecules of YH were span by 1 base pair) and was determined by Job's plot. The thermodynamic parameters suggested exothermic binding, which was favored by negative enthalpy and positive entropy changes from both isothermal titration calorimetry and temperature-dependent fluorescence experiment. Salt-dependent fluorescence suggested that the interaction between the ligand and DNA was governed by nonpolyelectrolytic forces. Kinetics experiment confirmed the static type of quenching. The results of iodide quenching, urea denaturation assay, dye displacement, DNA melting, and in silico molecular docking (MD) suggested groove binding of YH to CT-DNA. Circular dichroism spectra confirmed minimal perturbation of CT-DNA with YH binding via groove region. Therefore, the groove binding mechanism of interaction was validated by biophysical techniques and in silico, MD approaches. The findings supported here may contribute to the development of new YH therapeutics possessing better efficacy and lesser side effects.

Toxicity Study and Binding Analysis of Newly Synthesized Antifungal N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazinecarbothioamide Derivative with Bovine Serum Albumin.

The presence of the p-aryl/cyclohexyl ring in the N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazine carbothioamide derivative (2C) is reported to enhance the antifungal properties when compared to those of itraconazole. Serum albumins present in plasma bind and transport ligands, including pharmaceuticals. This study explored 2C interactions with BSA using spectroscopic methods such as fluorescence and UV-visible spectroscopy. In order to acquire a deeper comprehension of how BSA interacts with binding pockets, a molecular docking study was carried out. The fluorescence of BSA was quenched by 2C via a static quenching mechanism since a decrease in quenching constants was observed from 1.27 × 105 to 1.14 × 105. Thermodynamic parameters indicated hydrogen and van der Waals forces responsible for the BSA-2C complex formation with binding constants ranging between 2.91 × 105 and 1.29 × 105, which suggest a strong binding interaction. Site marker studies displayed that 2C binds to BSA's subdomains IIA and IIIA. Molecular docking studies were conducted to further comprehend the molecular mechanism of the BSA-2C interaction. The toxicity of 2C was predicted by Derek Nexus software. Human and mammalian carcinogenicity and skin sensitivity predictions were associated with a reasoning level of equivocal, inferring 2C to be a potential drug candidate.