Discovery of potent Covid-19 main protease inhibitors using integrated drug-repurposing strategy.

The emergence and rapid spreading of novel SARS-CoV-2 across the globe represent an imminent threat to public health. Novel antiviral therapies are urgently needed to overcome this pandemic. Given the significant role of the main protease of Covid-19 for virus replication, we performed a drug-repurposing study using the recently deposited main protease structure, 6LU7. For instance, pharmacophore- and e-pharmacophore-based hypotheses such as AARRH and AARR, respectively, were developed using available small molecule inhibitors and utilized in the screening of the DrugBank repository. Further, a hierarchical docking protocol was implemented with the support of the Glide algorithm. The resultant compounds were then examined for their binding free energy against the main protease of Covid-19 by means of the Prime-MM/GBSA algorithm. Most importantly, the machine learning-based AutoQSAR algorithm was used to predict the antiviral activities of resultant compounds. The hit molecules were also examined for their drug-likeness and toxicity parameters through the QikProp algorithm. Finally, the hit compounds activity against the main protease was validated using molecular dynamics simulation studies. Overall, the present analysis yielded two potential inhibitors (DB02986 and DB08573) that are predicted to bind with the main protease of Covid-19 better than currently used drug molecules such as N3 (cocrystallized native ligand), lopinavir, and ritonavir.

Exploring natural compounds for the management of non-small cell lung cancer.

A growing incidence of drug resistance and tumour proliferation in non-small cell lung cancer escalates the urge for potential lead molecules. The plant-derived natural compounds have played a pivotal role in potential therapeutic agents owing to its versatility and low toxicity over the past decades. In this study, we have executed an in-silico based screening of 1574 natural compounds against the ß-catenin via an integrated pharmacophore approach. Further investigation revealed that Mucronulatol and 7,4'-dihydroxyhomoisoflavanone possess a higher Glide score (-4.748 and -3.943 kcal/mol), binding affinity (-44.763 and -41.883 kcal/mol) alongside drug-likeness property than the iCRT5. Moreover, these compounds are reported to have cytotoxicity against lung cancer cell lines with an IC50 value of 6.74 µM and 8.99 µM respectively. Furthermore, dynamic studies were employed to determine the structural stability and we hope that the lead molecules proposed in this study could effectively inhibit the ß-catenin pathway associated with NSCLC.

Exploring ß-Tubulin Inhibitors from Plant Origin using Computational Approach.

INTRODUCTION: ß-Tubulin is an important target for the binding of anti-cancer drugs, in particular, paclitaxel (taxol), vinblastine and epothilone. However, mutations in ß-tubulin structure give resistance to chemotherapeutic agents. Notably, mutations at R306C, F270 V, L217R, L228F, A185T and A248V positions in ß-tubulin give high resistance for paclitaxel binding. OBJECTIVE: To discover novel inhibitors of ß-tubulin from natural sources, particularly alkaloids, using a virtual screening approach. METHODOLOGY: A virtual screening approach was employed to find potent lead molecules from the Naturally-occurring Plant-based Anti-cancer Compound-activity Target (NPACT) database. Alkaloids have great potential to be anti-cancer agents. Therefore, we have screened all alkaloids from a total of 1574 molecules from the NPACT database for our study. Initially, Molinspiration and DataWarrior programs were utilised to calculate pharmacokinetics and toxicity risks of the alkaloids, respectively. Subsequently, AutoDock algorithm was employed to understand the binding efficiency of alkaloids against ß-tubulin. The binding affinity of the docked complex was confirmed by means of an intermolecular interaction study. Moreover, oral toxicity was predicted by using ProTox program. Further, metabolising capacity of drugs was studied by using SmartCYP software. Additionally, scaffold analysis was done with the help of scaffold trees and dendrograms, providing knowledge about the building blocks for parent-compound synthesis. RESULTS: Overall, the results of our computational analysis indicate that isostrychnine, obtained from Strychnosnux-vomica, satisfies pharmacokinetic and bioavailability properties, binds efficiently with ß-tubulin. Thus, it could be a promising lead for the treatment of paclitaxel resistant cancer types. CONCLUSION: This is the first observation of inhibitory activity of isostrychnine against ß-tubulin and warrants further experimental investigation. Copyright © 2016 John Wiley & Sons, Ltd.