An environmentally friendly method to remove and utilize the highly toxic strychnine in other products based on proton-transfer complexation

Charge-transfer chemistry of two corticosteroids used adjunctively to treat COVID-19. Part II: The CT reaction of hydrocortisone and dexamethasone donors with TCNQ and fluoranil acceptors in five organic solvents

Hydrocortisone (termed as D1) and dexamethasone (termed as D2) are corticosteroids currently used to treat COVID-19. COVID-19 is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Exploring additional chemical properties of drugs used in the treatment protocols for COVID-19 could help scientists alike improve these treatment protocols and potentially even the vaccines (i.e., Janssen, Moderna, AstraZeneca, Pfizer-BioNTech). In this work, the charge-transfer (CT) properties of these two corticosteroids (D1 and D2) with two universal acceptors: 7,8,8-tetracyanoquinodimethane (termed as TCNQ) and fluoranil (termed as TFQ) in five different solvents were investigated. The examined solvents were MeOH, EtOH, MeCN, CH₂Cl₂, and CHCl₃. The CT interactions formed stable corticosteroid CT complexes in all examined solvents. Several spectroscopic parameters were derived, and the oscillator strength (f) and transition dipole moment (μ_e.g.) values revealed that the interaction between the investigated corticosteroids with TCNQ acceptor is much stronger than their interaction with TFQ acceptor. The CT interactions were proposed to process via n → π* transition.

Charge-transfer chemistry of two corticosteroids used adjunctively to treat COVID-19. Part I: Complexation of hydrocortisone and dexamethasone donors with DDQ acceptor in five organic solvents

COVID-19 is the disease caused by a novel coronavirus (CoV) named the severe acute respiratory syndrome coronavirus 2 (termed SARS coronavirus 2 or SARS-CoV-2). Since the first case reported in December 2019, infections caused by this novel virus have led to a continuous global pandemic that has placed an unprecedented burden on health, economic, and social systems worldwide. In response, multiple therapeutic options have been developed to stop this pandemic. One of these options is based on traditional corticosteroids, however, chemical modifications to enhance their efficacy remain largely unexplored. Obtaining additional insight into the chemical and physical properties of pharmacologically effective drugs used to combat COVID-19 will help physicians and researchers alike to improve current treatments and vaccines (i.e., Pfizer-BioNTech, AstraZeneca, Moderna, Janssen). Herein, we examined the charge-transfer properties of two corticosteroids used as adjunctive therapies in the treatment of COVID-19, hydrocortisone and dexamethasone, as donors with 2,3-dichloro-5,6-dicyano-p-benzoquinone as an acceptor in various solvents. We found that the examined donors reacted strongly with the acceptor in CH₂Cl₂ and CHCl₃ solvents to create stable compounds with novel clinical potential.

Charge-transfer chemistry of azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part II: Complexation with several π-acceptors (PA, CLA, CHL)

Finding a vaccine or cure for the coronavirus disease (COVID-19) responsible for the worldwide pandemic and its economic, medical, and psychological burdens is one of the most pressing issues presently facing the global community. One of the current treatment protocols involves the antibiotic azithromycin (AZM) alone or in combination with other compounds. Obtaining additional insight into the charge-transfer (CT) chemistry of this antibiotic could help researchers and clinicians to improve such treatment protocols. Toward this aim, we investigated the CT interactions between AZM and three π-acceptors: picric acid (PA), chloranilic acid (CLA), and chloranil (CHL) in MeOH solvent. AZM formed colored products at a 1:1 stoichiometry with the acceptors through intermolecular hydrogen bonding. An n → π* interaction was also proposed for the AZM-CHL CT product. The synthesized CT products had markedly different morphologies from the free reactants, exhibiting a semi-crystalline structure composed of spherical particles with diameters ranging from 50 to 90 nm.

Synthesis, characterization, antimicrobial and DNA binding properties of an organic charge transfer complex obtained from pyrazole and chloranilic acid

The chemistry of an organic charge transfer complex (CT complex) between pyrazole (donor) and chloranilic acid (acceptor) has been explored in ethanol at room temperature. The synthesized complex has been characterized by various techniques such as FTIR, NMR, Single crystal X-ray diffraction and UV-visible spectroscopy. These techniques indicate that the cation and anion are joined together by the weak hydrogen bonding. This molecular framework is a result of inter N⁺-H⋯O^- bonding between donor and acceptor moieties. The elemental analysis and FTIR spectrum of semi-crystal complex along with Job's plot indicate the formation of 2: 1 HBCT-complex. The bioorganic chemistry of the present CT complex is established well toward antimicrobial screening and DNA binding capabilities. Antimicrobial activity was screened for gram positive and gram negative bacteria and various fungi. Molecular docking shows that the CT complex binds perfectly with the B-DNA and reveals free energy of binding (FEB) value of -198.4 kcal mol^-1. TD-DFT calculations using basis set B3LYP/6-311G^** give theoretical confirmation along with HOMO (-3.9421 eV) → LUMO (-2.4903 eV) electronic energy gap (ΔE) to be 1.4521 eV. Theoretical analysis corroborates well the biological properties.

Reliability of miRNA Analysis from Fixed and Paraffin-Embedded Tissues

In clinical practice, patients’ tissues are fixed and paraffin-embedded in order to enable histological diagnosis. Nowadays, those tissues are also used for molecular characterization. Formalin is the most used fixative worldwide, and Bouin’s solution in some worldwide institutions. Among molecular targets, micro RNAs (miRNAs), the single-stranded non-coding RNAs comprised of 18 to 24 nucleotides, have been demonstrated to be resistant to fixation and paraffin-embedding processes, with consequent possible application in clinical practice. In the present study, let-7e-5p, miR-423-3p, miR-92a-1-5p, miR-30d-5p, miR-155-5p, miR-200a-3p, and miR-429 were investigated in formalin and matched Bouin’s solution-fixed tissues of high grade serous ovarian cancers by means of real-time and droplet digital PCR (ddPCR). Micro RNAs were detectable and analyzable in both formalin- and Bouin’s-fixed specimens, but on average, higher Ct values and lower copies/µL were found in Bouin’s-fixed samples. Data from formalin-fixed samples correlated significantly for most targets with Bouin’s ones, except for let-7e-5p and miR-155-5p. This study shows that miRNAs are analyzable in both formalin- and Bouin’s-fixed specimens, with the possibility, after proper data normalization, to compare miRNA-based data from formalin-fixed samples to those of Bouin’s-fixed ones.

Spectrophotometric and photocatalytic studies of H-bonded charge transfer complex of oxalic acid with imidazole: single crystal XRD, experimental and DFT/TD-DFT studies

The photocatalytic activity of a new CT complex was tested. Spectrophotometric studies were performed to understand its formation through N⁺–H⋯O⁻ hydrogen bonding, and the structure was confirmed by single crystal XRD.

UV-Vis, FTIR, 1H, 13C NMR spectra and thermal studies of charge transfer complexes formed in the reaction of Gliclazide with π- and σ-electron acceptors

Charge transfer interactions (CT) between a gliclazide (GLC) donor and a picric acid (PA) π acceptor or iodine σ acceptor, were studied in a chloroform solution and in the solid state. UV-vis spectroscopy elucidated the formation of the complexes, and allowed determination of the stoichiometry, stability constants (K), and thermodynamic quantities (ΔG°, ΔH°, and ΔS°), and spectroscopic properties such as the molar extinction coefficient (ε_CT), oscillator strength (f), transition dipole moment (μ_EN), and ionization potential (I_p). Beer's law was obeyed over the 2-8 and 4-12 μg mL^-1 concentration ranges for GLC with PA (method A) and I₂ (method B), respectively, with correlation coefficients of 0.9986 and 0.9989. The limits of detection (LOD) and limits of quantification (LOQ) have also been reported. The 1:1 stoichiometric CT complexes were synthesized and characterized by FTIR, ¹H, and ¹³C NMR spectroscopy. The results indicated a favorable proton migration from PA to the donor molecule, and an interaction between the NH of GLC and iodine. Thermogravimetric analysis techniques (TGA/DTA) and differential scanning calorimetry (DSC) were used to determine the thermal stability of the synthesized CT complex. The kinetic parameters (ΔG*, ΔH*, and ΔS*) were calculated from thermal decomposition data using the Coats-Redfern method.