Experimental and Theoretical Study of Effect of Allium sativum Extracts as Corrosion Inhibitor on Mild Steel in 1 M HCl Medium

Experimental accompanied with computational (atomic/electronic)-level simulation investigations of Polygonum cuspidatum root extract as sustainable corrosion inhibitor for mild steel in aggressive corrosive media

This study investigates the corrosion inhibition potential of Polygonum cuspidatum root extract (PCRE) on mild steel in a 0.5 M HCl acidic environment. Herein, various techniques including electrochemical and gravimetric measurements were employed, along with scanning electron microscopy (SEM) and contact angle (CA) measurements for surface morphology analysis. The impedance study revealed a concentration-dependent enhancement in corrosion resistance, classifying PCRE as a mixed-type inhibitor (i.e., inhibits both anodic and cathodic reactions). The highest efficiency, 96.71% at 298 K, was observed at a 1000-ppm PCRE concentration. Langmuir model computations suggested chemisorption and physisorption of PCRE on the electrode substrate. Increased Rp (from 28.648 to 174.01 Ω) and Rct (185.74 Ω cm2) at 1000 ppm demonstrated improved corrosion resistance. Additionally, SEM analysis displayed a uniform, protective surface, reducing metal degradation. Theoretical calculations highlighted strong interactions between PCRE and mild steel, with a low energy gap (ΔE), as follows: 1-O-methylemodin (2.267 eV) < emodin (2.288 eV) < emodin-1-O-glucoside (2.343 eV) < piceid (2.931 eV) < resveratrol (2.952 eV), confirming PCRE's excellent micro-level anti-corrosion capabilities. This eco-benign corrosion inhibitor offers sustainable, low-toxicity protection, cost-effectiveness, and versatile performance, surpassing commercial counterparts while aligning with sustainability goals.

Design, syntheses, theoretical calculations, MM-GBSA, potential anti-cancer and enzyme activities of novel Schiff base compounds

In this study, new Schiff base compounds (SB-F-OH, SB-Cl-OH and SB-Br-OH) were derived from chalcone-derived amine compounds containing halogen groups and 4-hydroxybenzaldehyde. Also, their phthalonitrile compounds (SB-F-CN, SB-Cl-CN and SB-Br-CN) have been synthesized. The structures of these compounds were elucidated by NMR, FT-IR and Mass spectroscopic methods. The quantum chemical parameters were calculated at B3LYP/6-31++g(d,p), HF/6-31++g(d,p) and M062X/6-31++g(d,p) levels. As the biological application of the synthesized compounds, (i) their inhibition properties of the synthesized compounds on Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) metabolic enzymes were investigated, and their potential anticancer activities against neuroblastoma (NB; SH-SY5Y) and healthy fibroblast (NIH-3T3) cell lines were determined by in vitro assays. All compounds showed inhibition at nanomolar level with the Ki values in the range of 97.86 ± 30.51-516.82 ± 31.42 nM for AChE, 33.21 ± 4.45-78.50 ± 8.91 nM for BChE, respectively. It has been determined that all tested compounds have a remarkable cytotoxic effect against SH-SY5Y, and IC50 values were significantly lower than NIH-3T3 cells. The lowest IC50 value was observed in SB-Cl-OH (7.48 ± 0.86 µM) and SB-Cl-CN (7.31 ± 0.69 µM). The molecular docking of the molecules was also investigated using crystal structure of AChE enzyme protein (PDB ID: 4M0E), crystal structure of BChE protein (PDB ID: 6R6V) and SH-SY5Y cancer protein (PDB ID: 2F3F, 3PBL and 5WIV). The ADME properties of the compounds were investigated. MM/GBSA method is calculated binding free energy. Afterwards, ADME/T analysis was performed to examine the some properties of the molecules.Communicated by Ramaswamy H. Sarma.

A comprehensive assessment of carbon steel corrosion inhibition by 1,10-phenanthroline in the acidic environment: insights from experimental and computational studies

1,10-Phenanthroline (PHN) is a nitrogen-containing heterocyclic organic compound that is widely used in a variety of applications, including chemosensors, biological studies, and pharmaceuticals, which promotes its use as an organic inhibitor to reduce corrosion of steel in acidic solution. In this regard, the inhibition ability of PHN was examined for carbon steel (C48) in a 1.0 M HCl environment by performing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), mass loss, and thermometric/kinetic. Additionally, scanning electron microscopy (SEM) was used to examine the surface morphology of C48 immersed in 1.0 M HCl protected with our inhibitor. According to the PDP tests, increasing the PHN concentration resulted in an improvement in corrosion inhibition efficiency. Besides, the maximum corrosion inhibition efficiency is about 90% at 328 K. Furthermore, the PDP assessments demonstrated that PHN functions as a mixed-type inhibitor. The adsorption analysis reveals that our title molecule mechanism is due to physical-chemical adsorption, as predicted by the Frumkin, Temkin, Freundlich, and Langmuir isotherms. The SEM technique exhibited that the corrosion barrier occurs due to the adsorption of the PHN compound through the metal/1.0 M HCl interface. In addition, the computational investigations based on a quantum calculation using density functional theory (DFT), reactivity (QTAIM, ELF, and LOL), and molecular-scale by Monte Carlo (MC) simulations confirmed the experimental results by providing further insight into the mode of adsorption of PHN on the metal surface, thus forming a protective film against corrosion on the C48 surface.

Molecular docking studies, anti-Alzheimer's disease, antidiabetic, and anti-acute myeloid leukemia potentials of narcissoside

In this research, we explored their capacity for Narcissoside antioxidant and anticholinergic, antidiabetic, and anti-acute myeloid leukaemia. Narcissoside's antioxidant activities were elucidated by the use of various bioanalytical assays. Narcissoside's radical scavenging activities were evaluated by DPPH^• and ABTS^•+ scavenging activities. On the other hand, IC₅₀ values were calculated for DPPH^•, and ABTS^•+ scavenging, acetylcholinesterase, and α-glucosidase inhibition effects of narcissoside. IC₅₀ values narcissoside, as 11.54 nM for AChE and 65.58 nM for α-glucosidase were calculated with % Activity-[Inhibitory] graphs. Then, ADME/T analysis of narcissoside molecule was performed to calculate the drug becoming parameters.

Synthesis, Spectroscopic Characterization, Antibacterial Activity, and Computational Studies of Novel Pyridazinone Derivatives

In this work, a novel series of pyridazinone derivatives (3-17) were synthesized and characterized by NMR (¹H and ¹³C), FT-IR spectroscopies, and ESI-MS methods. All synthesized compounds were screened for their antibacterial activities against Staphylococcus aureus (Methicillin-resistant), Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, and Acinetobacter baumannii. Among the series, compounds 7 and 13 were found to be active against S. aureus (MRSA), P. aeruginosa, and A. baumannii with the lowest MIC value range of 3.74-8.92 µM. Afterwards, DFT calculations of B3LYP/6-31++G(d,p) level were carried out to investigate geometry structures, frontier molecular orbital, molecular electrostatic potential maps, and gap energies of the synthesized compounds. In addition, the activities of these compounds against various bacterial proteins were compared with molecular-docking calculations. Finally, ADMET studies were performed to investigate the possibility of using of the target compounds as drugs.

Synthesis, biological activity and docking calculations of bis-naphthoquinone derivatives from Lawsone

Some metabolic enzyme inhibitors can be used as Multi-target-Directed-Ligands (MTDL) in Medicinal chemistry therefore, synthesis and determination of alternative inhibitors are essential. In this study, novel bis-napthoquinone derivatives (5a-o) were synthesized through a multi-component cascade reaction of two molecules of 2-hydroxy-1,4-naphthoquinone with an aromatic aldehyde in basic media using triethylamine as a catalyst. This novel heterocyclic derivatives (5a-o) are applied to inhibit the carbonic anhydrase (hCA I and hCA II) isoform in low levels of nano molecules with Ki values exist between 4.62 ± 1.01 to 70.45 ± 9.03 nM for hCA I and for hCA II which is physiologically dominant K_is values are in the range of 5.61 ± 1.04 to 73.26 ± 10.25 nM. Further these novel derivatives (5a-o) efficiently inhibit AChE with Ki values in the range of 0.13 ± 0.02 to 3.16 ± 0.56 nM. The compounds are also applied for BChE with Ki values varying between 0.50 ± 0.10 to 9.23 ± 1.15 nM. For α-glycosidase, the most efficient Ki values of 5e and 5f are 76.14 ± 9.60 and 95.27 ± 12.55 nM respectively. Finally, molecular docking calculations against enzymes (acetylcholinesterase, butyrylcholinesterase, and the human carbonic anhydrase I and II) are compared using biological activities of heterocyclic derivatives. After these calculations, an ADME/T analysis is performed to study the future medicinal use of heterocyclic derivatives from lawsone.

ADME properties, bioactivity and molecular docking studies of 4-amino-chalcone derivatives: new analogues for the treatment of Alzheimer, glaucoma and epileptic diseases

In this study, in vitro inhibition effects of (E)-1-(4-aminophenyl)-3-(aryl) prop-2-en-1-one (4-amino-chalcones) derivatives (3a-o) on acetylcholinesterase (AChE) enzyme and human erythrocyte carbonic anhydrase I and II isoenzymes (hCA I- II) were investigated. And also, the biological activities of 4-amino-chalcone derivatives against enzymes which names are acetylcholinesterase (PDB ID: 1OCE), human Carbonic Anhydrase I (PDB ID: 2CAB), human carbonic anhydrase II (PDB ID: 3DC3), were compared. After the results obtained, ADME/T analysis was performed in order to use 4-amino-chalcone derivatives as a drug in the future. Effective inhibitors of carbonic anhydrase I and II isozymes (hCAI and II) and acetylcholinesterase (AChE) enzymes with Ki values in the range of 2.55 ± 0.35-11.75 ± 3.57 nM for hCA I, 4.31 ± 0.78-17.55 ± 5.86 nM for hCA II and 96.01 ± 25.34-1411.41 ± 32.88 nM for AChE, respectively, were the 4-amino-chalcone derivatives (3a-o) molecules.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-021-00094-x.