Atom based 3D QSAR and Fingerprint based 2D QSAR of Novel Molecules as MmpL3 receptor inhibitors for Mycobacterium tuberculosis

Tuberculosis is one of the leading cause of increase in mortality rate in today’s health care scenario. Due to increase frequency of drug resistant TB it is prudent to find new targets and promising targets for anti-tubercular activity. MmpL3 (Mycobacterial Membrane Protein Large 3) is one of the most effective and promiscuous targets for development of new drug for anti-tubercular therapy due to its cross resistance inhibition property. In this study we have presented atom based 3D QSAR and finger print based 2D QSAR models to study different structural and functional groups of Adamantyl urea derivatives and their action in MmpL3 inhibitory activity which will provide us the insight for designing better and far more effective anti TB drugs.

Plasmodium falciparum Dihydroorotate Dehydrogenase, Fragment-based Drug Design, 2D-QSAR, DFT Calculation, Lead Optimization, Induced Fit Docking

Plasmodium falciparum dihydroorotate dehydrogenase (PfDODH) is one of the enzymes currently explored in the treatment of malaria. Although there is currently no clinically approved drug targeting PfDODH, many of the compounds in clinical trials have [1, 2, 4,] triazolo [1, 5-a] pyrimidin-7-amine backbone structure. This study sought to design new compounds from the fragments of known experimental inhibitors of PfDODH. Nine experimental compounds retrieved from Drug Bank online were downloaded and broken into fragments using Schrodinger power shell; the fragments were recombined to generate new ligand structures using BREED algorithm. The new compounds were docked with PfDODH crystal structure, after which the compounds were filtered with extensive drug-likeness and toxicity parameters. A 2D-QSAR model was built using the multiple linear regression method and externally validated. The compounds electronic behaviours were studied using DFT calculations. Structural investigation of the six designed compounds, which had lower binding energies than the standard inhibitors, showed that five of them had [1, 2, 4,] triazolo [1, 5-a] pyrimidin-7-amine moieties and interacted with essential residues at the PfDODH binding site. In addition to their drug-like and pharmacokinetic properties, they also showed minimal toxicities. The externally validated 2D-QSAR model with R2 and Q2 values of 0.6852 and 0.6691, confirmed the inhibitory prowess of these compounds against PfDODH. The DFT calculations showed regions of the molecules prone to electrophilic and nucleophilic attack. The current study thus provides insight into the development of a new set of potent PfDODH inhibitors.

Physicochemical, Interaction & Topological Descriptors vs. hMAO-A Inhibition of Aplysinopsin Analogs: A Boulevard to the Discovery of Semi-Synthetic Anti-Depression Agents

Background: Neurological disorder, depression is the globally 4th leading cause of chronic disabilities in human beings. Objective: This study aimed to model a 2D-QSAR equation that can facilitate the researchers to design better aplysinopsin analogs with potent hMAO-A inhibition. Methods: Aplysinopsin analogs dataset were subjected to ADME assessment for drug-likeness suitability using StarDrop software before modeled equation. 2D-QSAR equations were generated using VLife MDS 4.6. Dataset was segregated into training and test set using different methodologies, followed by variable selection. Model development was done using principal component regression, partial least square regression, and multiple regression. Results: The dataset has successfully qualified the drug-likeness criteria in ADME simulation, with more than 90% of molecules cleared the ideal conditions including intrinsic solubility, hydrophobicity, CYP3A4 2C9pKi, hERG pIC50, etc. 112 models were developed using multiparametric consideration of methodologies. The best six models were discussed with their extent of significance and prediction capabilities. ALP97 was emerged out as the most significant model out of all, with ~83% of the variance in the training set, the internal predictive ability of ~74% while having the external predictive capability of ~79%. Conclusion: ADME assessment suggested that aplysinopsin analogs are worth investigating. Interaction among the descriptors in a way of summation or multiplication products, are quite influential and yielding significant 2D-QSAR models with good prediction efficiency. This model can be used for the design of a more potent hMAO-A inhibitor having an aplysinopsin scaffold, which can then contribute to the treatment of depression and other neurological disorders.

Design, Synthesis, Biological Evaluation, 2D-QSAR Modeling, and Molecular Docking Studies of Novel 1H-3-Indolyl Derivatives as Significant Antioxidants

Novel candidates of 3-(4-(thiophen-2-yl)-pyridin/pyran/pyrimidin/pyrazol-2-yl)-1H-indole derivatives (2–12) were designed by pairing the pyridine/pyrane/pyrimidine/pyrazole heterocycles with indole and thiophene to investigate their potential activities as (2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) inhibitors. The purpose of these derivatives’ modification is to create high-efficiency antioxidants, especially against ABTS, as a result of the efficiency of this set of key heterocycles in the inhibition of ROS. Herein, 2D QSAR modeling was performed to recommend the most promising members for further in vitro investigations. Furthermore, the pharmacological assay for antioxidant activity evaluation of the yielded indole-based heterocycles was tested against ABTS (2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid); by utilizing ascorbic acid as the standard. Candidate 10 showed higher antioxidant activity (IC50 = 28.23 μg/mL) than ascorbic acid itself which achieved (IC50 = 30.03 μg/mL). Moreover, molecular docking studies were performed for the newly designed and synthesized drug candidates to propose their mechanism of action as promising cytochrome c peroxidase inhibitors compared to ascorbic acid as a reference standard. Our findings could be promising in the medicinal chemistry scope for further optimization of the newly designed and synthesized compounds regarding the introduced structure-activity relationship study (SAR) in order to get a superior antioxidant lead compound in the near future.

Structure Activity Design, Synthesis and Biological Activity of Newer Imidazole-Triazine Clubbed Derivative as Antimicrobial and Antitubercular Agents

Background: Imidazole and triazine derivatives act as antimicrobial and antitubercular agents. 2D-QSAR determination estimates the pharmacological activity on the basis of thermodynamic properties of the structure. Objective: The structural arrangements and thermodynamic properties of the imidazole derivatives are necessary for the enhancement of pharmacological activity. So imidazole-triazine clubbed derivatives were designed on the bases of molecular modeling 2D-QSAR study of antitubercular activity. Methods: PLSR method was applied for 2D-QSAR determination of the (Z)-5-ethylidene-3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-2-phenyl-3,5-dihydro-4H-imidazol-4-one (B1-B10). The designed compounds were synthesized and spectrally evicted by IR, 1H NMR, 13C NMR, Mass spectra data as well as biologically screened opposite different antitubercular and antimicrobial species. Result: Compounds B4, B6, B7 were founds potent against different antimicrobial species. Compound B3 was more effective against M. tuberculosis H37Rv. Statistically significant QSAR model generated by PLSR methods shows external r2=0.9775 and internal q2=0.2798 predictive ability. Whereas, the model incorporates with three parameters PolarSurfaceAreaExcluding P and S, MomInertiaY and SsCH3count with their corresponding values for each molecule. Conclusion: 2D-QSAR study advised antitubercular activity directly proportional to total surface area of the polar atoms having molecules and moment of inertia on Y-axis. Whereas, inversely proportional to methyl group joined with single bond. The present study afforded favorable results which were further used to generate lead target molecules.