Current Chemical Biology - Volume 15, Issue 3, 2021

The virus SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) causes COVID 19 (CoronaVIrus Disease 19), a global pandemic with multi-organ failure, resulting in high morbidity and mortality. Some individuals are more vulnerable than others and have deleterious consequences following covid- 19. It has been postulated that Heme oxygenase-1 (HO-1) reduction and free heme may contribute to many of the inflammatory phenomena observed in COVID-19 patients. Therefore, HO-1 inducers could prove to be potential therapeutic or preventive agents for COVID 19. Many of the natural compounds present in fruits and vegetables, such as polyphenols, were able to induce HO-1. The aim of this review is to focus on the main foods containing bioactive compounds able to induce HO-1 for an informed choice of foods to use to counteract damage from SARS-CoV-2 infection.

Background: The most current reported methods of chalcogen insertion into BODIPY’s nuclei are based on nucleophilic substitution reactions of halogenated derivatives, metal-catalyzed cross-coupling reactions, or assistance by radical mechanisms. Recent reports describe Oxidative Nucleophilic Hydrogen Substitution (ONHS) reactions involving the functionalization of BODIPY nuclei by thiols, but the generalities of the strategy for other chalcogens was not yet demonstrated. Herein we report our contribution on the selenium-functionalization of BODIPY by ONHS in high yield. Objective: Aryl-Se-functionalization of 2,6-brominated BODIPY’s nuclei by ONHS reaction. Methods: The procedure consists of a direct reaction of 2,6-brominated BODIPYs with in situ generated PhSeH in THF, at room temperature, under a nitrogen atmosphere. The corresponding products were isolated and purified by conventional flash column chromatography. Full structure characterization was performed by 1H, 13C, 19F, and 77Se NMR and DFT calculation. Results: Densely functionalized 2,6-dibrominated/3,5-diseleno-BODIPYs were obtained as corresponding products, leading to versatile molecular scaffolds. Their structural features were contrary to those initially expected by the original experimental applied conditions. A mechanistic investigation was performed to conclude that ONHS reaction is governing the transformation, thereby damaging the nucleophilic substitution of the halogen atoms. Conclusion: To sum up, new densely functionalized BODIPY derivatives were synthesized by a highly selective, simple, fast, metal-free, and efficient insertion of PhSe- residues into the 3,5-positions, governed by an Oxidative Nucleophilic Hydrogen Substitution (ONHS) reaction in high yields. It was observed that the presence of halogen (Br) into the 2,6-positions of the BODIPY core is mandatory for the ONHS reaction, which is completely inert when the 2,6-hydrogenated analogues are used in the same experimental conditions.

Background and Objective: The objective of the present study is to use docking and ADME analysis to determine if the cardenolides of Asclepias subulata are potential stabilizing drugs of the p53-Y220C mutant. Materials and Methods: Two different receptors, wild-type p53, and the mutant p53-Y220C, were used for docking. Three independent stochastic series were performed, with 60,000 poses considered, and the 30 best poses were selected. ADME analysis was performed using SwissADME. Results: Docking experiments revealed that corotoxigenin 3-O-glucopyranoside and calotropin interact with the cleft, so they were considered potential stabilizers of the p53-Y220C mutant comparable to the control drug 9H5, which was able to predict a position very similar to that already reported in the crystallographic structure. The ADME predicted that calotropin and desglucouzarin have more favorable pharmacokinetic parameters. Both molecules are predicted to be absorbed from the GIT. Conclusion: Calotropin of A. subulata is predicted to be a potential drug for p53-Y220C, because it binds to the cleft of the mutant and has favorable pharmacokinetic parameters. Corotoxigenin 3- O-glucopyranoside also binds to the Y220C cleft, but had less favorable pharmacokinetic parameters. These results have a future impact since calotropin could be used for the treatment of some types of cancer.

Background: Carboxylesterase Notum is a negative regulator of Wnt signaling. Notum carboxylesterase is a carboxylic ester hydrolase enzyme that functions as a negative feedback regulator of Wnt proteins by depalmitoylation reaction. It is of great importance to understand the pathway of Wnt regulation because, conversely, misregulation of Wnt signaling is a telltale sign of cancer and other degenerative diseases. The Wnt inhibition is important in the control of colorectal cancer. Objective: In the present study, we carried out a QSAR analysis of a series of reported compounds with carboxylesterase Notum inhibitory activity using multiple regression analysis. A series of 83 compound datasets of pyrrole derivatives with carboxy Notum inhibitory values were taken from the reported literature. Methods: The study was performed by conducting multiple linear regression analysis followed by validation of the model. The multiple linear regression (MLR) models with the highest coefficients of correlation (R2) and explained variance in leave-one-out (Q2 LOO) prediction and leave- manyout (Q2 LMO) were selected for the whole dataset. The developed models were subjected to internal and external validation. The reliability of the predicted model was checked by plotting the Williams plot. The docking methodology was performed using Autodock 4 for the designed compounds to study the interaction between the ligand and the receptor. Results: The best model generated exhibited an r2 value of 0.7413, Q2LOO =0.6379, Q2LMO =0.6368. Novel compounds of phenyl pyrrolidine were designed based on generated QSAR equations. The carboxylesterase Notum inhibitory activity was predicted using the QSAR equations. The docking studies were carried out for designed compounds using Autodock against Carboxylesterase Notum esterase. Conclusion: From the results, the designed compounds were found to inhibit Notum Carboxylase. Thus, the study led to the development of a novel lead compound for Carboxylesterase Notum.

Background: Molecule compatibility is an important factor to be considered before preparing antibody-targeted liposomes, stealth-liposomes, and stealth antibody-targeted liposomes. Objective: To determine the intermolecular interaction of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamide- N-[methoxy(polyethyleneglycol)-2000] (ammonium salt), DOPE PEG2000 and Anti-SNAP25 (AS25) in 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) monolayer, and their liposomes. Methods: In this study, DPPC was used to create a monolayer mimicking the half membrane of liposomes to investigate its interactions with a polyclonal antibody, AS25, and DOPE PEG2000, which are based on Langmuir-Blodgett (LB) techniques. The surface morphology of DPPC-AS25 and DPPC-DOPE PEG2000-AS25 bilayers were also imaged and analyzed by using atomic force microscopy (AFM) to support the LB findings. The LB findings were then utilized as a reference to prepare DPPC liposomes in this work. Results: The best mole ratio of DPPC-DOPE PEG2000, determined to be 50 to 1, was used to study the interaction with the polyclonal antibody AS25. The free energy of mixing (ΔGmix) of DPPC- DOPE PEG2000-AS25 was more negative than DPPC-AS25 in the entire investigated ranges, indicating that the ternary mixture of DPPC-DOPE PEG2000-AS25 was more compatible than the binary mixture of DPPC-AS25. The presence of DOPE PEG2000 in DPPC-AS25 increased the fluidity of the membrane, which resulted in a greater interaction of AS25 with DPPC. Conclusion: The constant values of particle size and zeta potential measurements of DPPC-DOPE PEG2000-AS25 liposomes showed agreement with the LB findings, indicating that LB is a good technique to predict precise liposomal formulations.

Background: The Murine Double Minute 2 (MDM2) protein is a well-studied primary negative regulator of the tumor suppressor p53 molecule. Therefore, nowadays many research studies have focused on the inhibition of MDM2 with potent inhibitors. Idasanutlin (RG7388) is a well-studied small molecule, the antagonist of MDM2 with potential antineoplastic activity. Nevertheless, the highly significant information pertaining to the free energy profile, intermediates, and the association of receptor and ligand components in the MDM2-idasanutlin complex remains unclear. Objective: To study the free energy profile of the MDM2-idasanutlin complex in terms of the Potential of Mean Force (PMF) method. Methods: We have used the PMF method coupled with umbrella sampling simulations to generate the free energy profile for the association of N-Terminal Domain (NTD) of MDM2 and idasanutlin along with a specific reaction coordinate for identifying transition states, intermediates as well as the relative stabilities of the endpoints. We also have determined the binding characteristics and interacting residues at the interface of the MDM2-idasanutlin complex from the Binding Free Energy (BFE) and Per Residue Energy Decomposition (PRED) analyses. Results: The PMF minima for the MDM2-idasanutlin complex was observed at a center of mass (CoM) distance of separation of 11 Å with dissociation energy of 17.5 kcal mol-1. As a function of the distance of separation of MDM2 from idasanutlin, we also studied the conformational dynamics as well as stability of the NTD of MDM2. We found that there is indeed a high binding affinity between MDM2 and idasanutlin (ΔGbinding = -3.19 kcal mol-1). We found that in MDM2, the residues MET54, VAL67, and LEU58 provide the highest energy input for the interaction between MDM2 and idasanutlin. Conclusion: Our results in this study illustrate the significant structural and binding features of the MDM2-idasanutlin complex that may be useful in the development of potent inhibitors of MDM2.