A Dispersion Corrected DFT Investigation of the Inclusion Complexation of Dexamethasone with ß-Cyclodextrin and Molecular Docking Study of Its Potential Activity against COVID-19.

The encapsulation mode of dexamethasone (Dex) into the cavity of ß-cyclodextrin (ß-CD), as well as its potential as an inhibitor of the COVID-19 main protease, were investigated using density functional theory with the recent dispersion corrections D4 and molecular docking calculations. Independent gradient model and natural bond orbital approaches allowed for the characterization of the host-guest interactions in the studied systems. Structural and energetic computation results revealed that hydrogen bonds and van der Waals interactions played significant roles in the stabilization of the formed Dex@ß-CD complex. The complexation energy significantly decreased from -179.50 kJ/mol in the gas phase to -74.14 kJ/mol in the aqueous phase. A molecular docking study was performed to investigate the inhibitory activity of dexamethasone against the COVID-19 target protein (PDB ID: 6LU7). The dexamethasone showed potential therapeutic activity as a SARS CoV-2 main protease inhibitor due to its strong binding to the active sites of the protein target, with predicted free energy of binding values of -29.97 and -32.19 kJ/mol as calculated from AutoDock4 and AutoDock Vina, respectively. This study was intended to explore the potential use of the Dex@ß-CD complex in drug delivery to enhance dexamethasone dissolution, thus improving its bioavailability and reducing its side effects.

Chemical Composition and Antioxidant, Anti-Inflammatory, and Enzyme Inhibitory Activities of an Endemic Species from Southern Algeria: Warionia saharae.

Warionia saharae Benth. & Coss. (Asteraceae) is an endemic species of North Africa naturally grown in the southwest of the Algerian Sahara. In the present study, this species' hydromethanolic leaf extract was investigated for its phenolic profile characterized by ultra-high-performance liquid chromatography coupled with a diode array detector and an electrospray mass spectrometer (UHPLC-DAD-ESI/MS). Additionally, the chemical composition of W. saharae was analyzed by gas chromatography-mass spectrometry, and its antioxidant potential was assessed through five in vitro tests: DPPH● scavenging activity, ABTS●+ scavenging assay, galvinoxyl scavenging activity, ferric reducing power (FRP), and cupric reducing antioxidant capacity. The UHPLC-DAD-ESI/MS analysis allowed the detection and quantification of 22 compounds, with taxifolin as the dominant compound. The GC-MS analysis allowed the identification of 37 compounds, and the antioxidant activity data indicate that W. saharae extract has a very high capacity to capture radicals due to its richness in compounds with antioxidant capacity. The extract also showed potent α-glucosidase inhibition as well as a good anti-inflammatory activity. However, weak anti-α-amylase and anticholinesterase activities were recorded. Moreover, an in silico docking study was performed to highlight possible interactions between three significant compounds identified in W. saharae extract and α-glucosidase enzyme.

3,4-Dimethoxy phenyl thiosemicarbazone as an effective corrosion inhibitor of copper under acidic solution: comprehensive experimental, characterization and theoretical investigations.

This study investigates the corrosion inhibition potential of 3,4-dimethoxy phenyl thiosemicarbazone (DMPTS) for copper in 1 M hydrochloric acid (HCl) solutions, aiming to disclose the mechanism behind its protective action. Through an integrative methodology encompassing electrochemical analyses-such as weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS)-we quantitatively evaluate the corrosion protection efficacy of DMPTS. It was determined that the optimal concentration of DMPTS markedly boosts the corrosion resistance of copper, achieving an impressive inhibition efficiency of up to 89% at 400 ppm. The formation of a protective layer on the copper surface, a critical aspect of DMPTS's inhibitory action, was characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). These techniques provided empirical evidence of surface morphology modifications and roughness changes, affirming the formation of a protective barrier against corrosion. A significant advancement in our study was the application of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, which identified chemical adsorption as the definitive mechanism of corrosion inhibition by DMPTS. The ATR-FTIR results explicitly demonstrated the specific interactions between DMPTS molecules and the copper surface, indicative of a robust protective adsorbed layer formation. This mechanistic insight, crucial to understanding the inhibitory process, aligns with the protective efficacy observed in electrochemical and surface analyses. Theoretical support, provided by the Quantum Theory of Atoms in Molecules (QTAIM) and quantum chemical computations, further validated the strong molecular interaction between DMPTS and copper, corroborating the experimental findings. Collectively, this research not only confirms the superior corrosion inhibition performance of DMPTS in an acidic setting but also elucidates the chemical adsorption mechanism as the foundation of its action, offering valuable insights for the development of effective corrosion inhibitors in industrial applications.

Molecular structures, chemical descriptors, and pancreatic lipase (1LPB) inhibition by natural products: a DFT investigation and molecular docking prediction.

Density functional theory (DFT) calculations and molecular docking have been carried out on natural products containing eugenol, gingerol, ascorbic acid, oleurpoein, piperine, hesperidin, quercetin, Luteolin, and curcumin in order to predict their biological activities and to analyze their pancreatic lipase inhibition. The biological activity predictions are based on the global and local chemical descriptors, namely, HOMO-LUMO gaps, chemical hardness, chemical potential, electrophilicity, dipole moment, and Fukui functions. Our findings show that the studied compounds can be divided into two groups based on the chemical descriptors; the first group is composed of eugenol, gingerol, ascorbic acid, and oleuropein and the second one is composed of piperine, hesperidin, quercetin, Luteolin, and curcumin depending on the HOMO-LUMO gaps and electrophilicity values predicting best reactivity for the second group than the first one. The frontier orbitals offer a deeper insight concerning the electron donor and electron acceptor capabilities, whereas the local descriptors resulting from Fukui functions put emphasis on the active sites of different candidate ligands. The molecular docking was performed in order to compare and identify the inhibition activity of the natural candidate ligands against pancreatic lipase which were compared to that of synthesized ones. The molecular docking results revealed that the Luteolin compound has the best binding affinity of -8.56 kcal/mol due to their unique molecular structure and the position of -OH aromatic substituents. Supplementary Information: The online version contains supplementary material available at 10.1007/s11224-023-02176-2.

Structural, electronic, and energetic investigations of acrolein adsorption on B36 borophene nanosheet: a dispersion-corrected DFT insight.

The adsorption of acrolein (AC) onto the surface of B36 borophene nanosheet was studied using dispersion-corrected density functional theory (DFT). The structural and electronic properties were scrutinized by several quantum chemical parameters such as HOMO-LUMO gap, condensed Fukui function, molecular electrostatic potential (ESP), and the density of states (DOS). The non-covalent interactions (NCI) were explored by combined reduced density gradient (RDG-NCI) and energy decomposition analysis (EDA) techniques. It was found that the adsorption of acrolein on both convex and concave surfaces of borophene is mainly governed by van der Waals interactions. Our calculations showed that the adsorption energy is strengthened and favored when multiple acrolein molecules adsorb on the edge sides of borophene through their terminal carbonyl oxygen atom. Furthermore, the calculated HOMO-LUMO energy gaps were significantly reduced upon adsorption affecting, therefore, the electrical conductance of borophene. These results should be useful in designing acrolein sensors.

Structural and energetic investigation on the host/guest inclusion process of benzyl isothiocyanate into ß-cyclodextrin using dispersion-corrected DFT calculations.

The formation of host-guest complex between benzyl isothiocyanate (BITC) and ß-cyclodextrin (ß-CD) was studied using dispersion-corrected density functional theory calculations. The complexation process was monitored using molecular docking simulations, natural bond orbital (NBO) technique, nuclear magnetic resonance (1H NMR) chemical shift calculations and non-covalent interactions (NCI) analysis. All these approaches are consistent with experimental findings. The calculated complexation energy was negative indicating the formation of inclusion complex. The most stable complexation of BITC involves the inclusion of its aromatic moiety in ß-CD cavity (model A) in accord with experimental NMR chemical shift data. The non-covalent interactions (NCI) based on the reduced density gradient (RDG) analysis reveal that mainly weak Van der Waals intermolecular interactions between BITC and ß-CD provide and ensure stability for the complexation process.