Studies on interaction between an imidazole derivative and bovine serum by spectral methods

Glucosamine and maltol anchored Zinc(II) complex of COVID-19 health supplement relevance: DFT collaborated spectroscopic formulation with profound biological implications

In association with other antiviral drugs, Zinc is specially administered to the patients suffering from novel coronavirus infectious disease (nCOVID). Zn, maltol, and glucosamine are famous food and drug additives. The supplements made from them are helpful in minimizing malnutrition problems, and in enhancing immune power. Due to the well-pronounced effects of all these three components in the food and medicinal industry, a novel sugar Zn(II) complex of the general composition, [Zn(gls)(mal)], where Hmal is maltol and Hgls is referred to as glucosamine, was synthesized and formulated. The physicochemical methods that were used to establish the molecular structure include elemental analysis, 1HNMR, FT-IR, UV–Vis., thermal and mass spectrometry. Physical properties like decomposition temperature and molar conductance were also examined. The experimental results at each step of characterization were validated/compared with density functionalized spectroscopic/spectrometric data using the LANL2DZ basis set for the metal atom and 6–31 g(d,p) for other atoms under the B3LYP functional. From the study, a suitable square planar geometry is suggested for the complex. Among biological implications, superoxide dismutation (SOD) and antimicrobial actions were studied. Also, virtual screening using SWISS ADME and Autodock 4.0 program (against 6X2B, SARS-CoV-2 u1S2q 2 RBD Up Spike Protein Trimer) were evaluated for the complex. Good interactions were scored by glucosamine and the complex. The results obtained from antimicrobial sensitivity indicate low inhibition zones, but from the SOD data, the complex has shown satisfactory antioxidant behavior. Therefore, the proposed food supplement could act as a good antioxidant agent and could keep the flora of the intestinal tract less disturbed while going through a metabolic pathway.

Studies of binding by 2-imidazolines to human serum albumin and alpha1-acid glycoprotein by high-performance affinity chromatography

2-Imidazoline drugs are used in a variety of applications, such as the treatment of hypertension and opioid withdrawal. It is known these drugs bind to serum proteins and have significant variations within this class of compounds in the overall level of this binding. However, little specific information is available on the interactions of these compounds with the two major transport proteins for many drugs, human serum albumin (HSA) and alpha₁-acid glycoprotein (AGP). This study examined binding by 2-imidazolines to these proteins by using 25 mm × 2.1 mm i.d. high-performance affinity microcolumns that contained HSA or AGP. The drugs that were examined were antazoline, clonidine, dexmedetomidine, lofexidine, moxonidine, phentolamine, and tizanidine, which represented a wide range of structures and pharmaceutical applications. The major metabolite of lofexidine, N-(2-aminoethyl)-2-(2,6-dichlorophenoxy) propenamide (LADP), was also examined. All these 2-imidazolines were found to have weak-to-moderate binding to HSA, with global affinities that ranged from 1.62 × 10² to 1.07 × 10⁴ M^-1 at pH 7.4 and 37 °C. These compounds had stronger binding with AGP, with global affinities constants ranging from 3.80 × 10² to 1.85 × 10⁴ M^-1. No stereoselectivity was observed by HSA for the enantiomers of dexmedetomidine, lofexidine, or LADP. However, AGP did show some stereoselectivity for lofexidine and LADP but not for dexmedetomidine. These results provide a better understanding of interactions of 2-imidazoline with HSA vs AGP in the circulation and of how this binding can change between drugs within this class of compounds.

Binding of pyridoxal, pyridoxal 5'-phosphate and derived hydrazones to bovine serum albumin in aqueous solution

In the present paper, the kinetics of a reaction between bovine serum albumin (BSA) and pyridoxal, pyridoxal 5'-phosphate was studied, apparent rate constant of product formation and dissociation as well as binding constants were determined. Pyridoxal 5'-phosphate hydrazones of isonicotinic, picolinic, 2-furoic, thiophene-2-carboxylic, pyrazinoic acids binding to BSA was studied by spectrofluorimetry, stability constants of the associates were calculated from experimental data using maximal likelihood approach. The changes in the secondary structure of BSA induced by hydrazones addition were studied by IR spectroscopy. New freely available software for curve fitting was developed as a part of the software kit designed for the solution chemistry and used for a specific problem of this study, IR spectra processing.

Improving surface and defect center chemistry of fluorescent nanodiamonds for imaging purposes--a review

Diamonds are widely used for jewelry owing to their superior optical properties accounting for their fascinating beauty. Beyond the sparkle, diamond is highly investigated in materials science for its remarkable properties. Recently, fluorescent defects in diamond, particularly the negatively charged nitrogen-vacancy (NV(-)) center, have gained much attention: The NV(-) center emits stable, nonbleaching fluorescence, and thus could be utilized in biolabeling, as a light source, or as a Förster resonance energy transfer donor. Even more remarkable are its spin properties: with the fluorescence intensity of the NV(-) center reacting to the presence of small magnetic fields, it can be utilized as a sensor for magnetic fields as small as the field of a single electron spin. However, a reproducible defect and surface and defect chemistry are crucial to all applications. In this article we review methods for using nanodiamonds for different imaging purposes. The article covers (1) dispersion of particles, (2) surface cleaning, (3) particle size selection and reduction, (4) defect properties, and (5) functionalization and attachment to nanostructures, e.g., scanning probe microscopy tips.

Synthesis, structural characterization and theoretical approach of the tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) cobalt(II)

The crystal structure of a new coordination compound tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) Co(II) complex ([Co(dcpip)3]Cl2) was measured with X-ray diffraction measurements. The compound is crystallizes triclinic, Pī space group. The ligand, 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline(dcpip), binds to Co(II) ions with a bis-dentate mode, and each Co(II) ion with a distorted octahedral coordination geometry. The calculated interaction energies of Co(II) with coordination atoms N are between 101.7-206.5 kJ/mol and 115.3-230.9 kJ/mol for B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) theoretical methods, respectively. The experimental Fourier transform infrared spectrum was assigned. The calculated IR based on B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) methods were performed and compared with experimental results. The UV-Vis experimental spectrum of [Co(dcpip)3]Cl2 was measured in methanol solution. The calculated electronic spectrum was performed with TD/B3LYP and TD/PBE1PBE methods with 6-31+G(∗) basis set. The first and second order hyperpolarizability for the compound was calculated. The calculated values of γtot are -1.5551344 × 10(-33) esu for B3LYP method and -1.3323259 × 10(-33) esu for PBE1PBE method. The nature bond orbital analysis and temperature dependence of the thermodynamic properties were calculated with the same methods.

Interaction of γ-Fe₂O₃ nanoparticles with fibrinogen

In this article, an attempt is made to analysis the binding mechanism of γ-Fe2O3 nanoparticles with fibrinogen by using a combination of circular dichroism, UV-vis, fluorescence spectroscopic and computational methods. The multi-spectroscopic data revealed that the complex easily formed between γ-Fe2O3 nanoparticles and fibrinogen by mainly hydrogen bonding forces. The binding constants of fibrinogen with γ-Fe2O3 nanoparticles were 2.24×10(7), 1.15×10(7) and 0.72×10(7)Lmol(-1) at 298, 304, and 310K, respectively. Furthermore, the results from circular dichroism, UV-vis, synchronous fluorescence, and three-dimensional fluorescence studies showed that the strong binding interaction of γ-Fe2O3 nanoparticles with fibrinogen induced an obvious perturbation in the protein secondary and tertiary structure. Moreover, the results of molecular modeling indicated the existence of the preferable binding site on fibrinogen for γ-Fe2O3 NPs model.