Ligand-based modeling of semicarbazones and thiosemicarbazones derivatives as Cathepsin B, H, and L inhibitors: A multi-target approach

Exploring the synthesis, characterization, and corrosion inhibition of new tris-thiosemicarbazone derivatives for acidic steel settings using computational and experimental studies

A novel two tri-thiosemicarbazones derivatives, namely 2,2',2''-((2-Hydroxybenzene-1,3,5-triyl)tris(methanylylidene))tris(N-benzylhydrazine-1-carbothioamide) (HBC) and 2,2',2''-((2-hydroxybenzene-1,3,5-triyl) tris (methanylylidene)) tris (N-allylhydrazine-1-carbothioamide) (HAC), have been synthesized and their chemical structures were determined using different spectroscopic and analytical approaches. Then, utilizing methods including open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy, the inhibitory effect of the synthesized thiosemicarbazones on mild steel (MS) in an acidic environment (0.5 M H2SO4) was thoroughly investigated. Remarkably, raising the concentration of our recently synthesized tri-thiosemicarbazones HBC and HAC increased the inhibitory efficiency values. The η values of the two investigated tri-thiosemicarbazones derivatives (HAC and HBC), at each concentration are extremely high, and the maximum values of the efficiencies are 98.5% with HAC and 98.8% with HBC at the 800 ppm. The inhibitors adsorbed on the mild steel surface and generated a charge and mass movement barrier that protected the metal from hostile ions. According to polarization curves, HBC and HAC act as mixed-type inhibitors. Electrochemical impedance testing revealed a notable rise in charge transfer resistance (Rct) readings to 4930-Ω cm2, alongside a reduction in the Constant Phase Element (CPE) value to 5.81 μF, suggesting increased effectiveness in preventing corrosion. Also, density functional theory (DFT) was applied to investigate the assembled tri-thiosemicarbazones HBC and HAC. Moreover, the adsorption mechanism of HBC and HAC on the mild steel surface was explored using Monte Carlo simulation. Finally, the theoretical outputs were discovered to support the practical outcomes.

Predictionof Environmental FateandToxicityofInsecticidesUsing Multi-Target QSAR Approach

Ecotoxicological risk assessments form the foundation of regulatory decisions for industrial chemicals used in various sectors. In this study, a multi-target-QSAR model established by a backpropagation neural network trained with the Levenberg-Marquardt (LM) algorithm was used to construct a statistically robust and easily interpretable Mt-QSAR model with high external predictability for the simultaneous prediction of the environmental fate in form of octanol-water partition coefficient (LogP), (BCF) and acute oral toxicity in mammals and birds (LD50rat ) and (LD50bird ) for a wide range of chemical structural classes of insecticides. Principal component analysis was performed on descriptors selected by the SW-MLR method, and the selected PCs were used for constructing the SW-MLR-PCA-ANN model. The developed well-trained model (RMSE=0.83, MPE=0.004, CCC=0.82, IIC=0.78, R2 =0.69) was statistically robust as indicated by the external validation parameters (RMSE=0.93, MPE=0.008, CCC=0.77, IIC=0.68, R2 =0.61). The AD of the developed Mt-QSAR model was also defined to identify the most reliable predictions. Finally, the missing values in the dataset for the aforementioned targets were predicted using the constructed Mt-QSAR model. The proposed approach can be used for simultaneous prediction of the environmental fate of new insecticides, especially ones that haven't been tested yet.

Discovery of 2-(furan-2-ylmethylene)hydrazine-1-carbothioamide derivatives as novel inhibitors of SARS-CoV-2 main protease

The COVID-19 posed a serious threat to human life and health, and SARS-CoV-2 M^pro has been considered as an attractive drug target for the treatment of COVID-19. Herein, we report 2-(furan-2-ylmethylene)hydrazine-1-carbothioamide derivatives as novel inhibitors of SARS-CoV-2 M^pro developed by in-house library screening and biological evaluation. Similarity search led to the identification of compound F8–S43 with the enzymatic IC₅₀ value of 10.76 μM. Further structure-based drug design and synthetic optimization uncovered compounds F8–B6 and F8–B22 as novel non-peptidomimetic inhibitors of M^pro with IC₅₀ values of 1.57 μM and 1.55 μM, respectively. Moreover, enzymatic kinetic assay and mass spectrometry demonstrated that F8–B6 was a reversible covalent inhibitor of M^pro. Besides, F8–B6 showed low cytotoxicity with CC₅₀ values of more than 100 μM in Vero and MDCK cells. Overall, these novel SARS-CoV-2 M^pro non-peptidomimetic inhibitors provide a useful starting point for further structural optimization.