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The nsp3 macrodomain is implicated in the viral replication, pathogenesis and host immune responses through the removal of ADP-ribosylation sites during infections of coronaviruses including the SARS-CoV-2. It has ever been modulated by macromolecules including the ADP-ribose until Ni and co-workers recently reported its inhibition and plasticity enhancement unprecedentedly by remdesivir metabolite, GS-441524, creating an opportunity for investigating other biodiverse small molecules such as β-Carboline (βC) alkaloids. In this study, 1497 βC analogues from the HiT2LEAD chemical database were screened, using computational approaches of Glide XP docking, molecular dynamics simulation and pk-CSM ADMET predictions. Selectively, βC ligands, 129, 584, 1303 and 1323 demonstrated higher binding affinities to the receptor, indicated by XP docking scores of -10.72, -10.01, -9.63 and -9.48 kcal/mol respectively than remdesivir and GS-441524 with -4.68 and -9.41 kcal/mol respectively. Consistently, their binding free energies were -36.07, -23.77, -24.07 and -17.76 kcal/mol respectively, while remdesivir and GS-441524 showed -21.22 and -24.20 kcal/mol respectively. Interestingly, the selected βC ligands displayed better stability and flexibility for enhancing the plasticity of the receptor than GS-441524, especially 129 and 1303. Their predicted ADMET parameters favour druggability and low expressions for toxicity. Thus, they are recommended as promising adjuvant/standalone anti-SARS-CoV-2 candidates for further study.Key words: SARS-CoV-2, nsp3 macrodomain, ADP-ribose, β-carboline, bioinformatics, drug design.

In this study, two novel derivatives of naphthalene-2-sulfonic acid: 6-(((1S,5R)-3,5-dichloro-2,4,6-triazabicyclo [z3.1.0]hex-3-en-1-yl)amino)-5-((E)-phenyldiazenyl)naphthalene-2-sulfonic acid (DTPS1) and (E)-6-((4,6-dichloro-1,3,5-triazine2-yl)amino)-4-hydroxy-3-(phenyldiazenyl)naphthalene-2-sulfonic acid (DTPS2) have been synthesized and characterized using FT-IR, UV-vis, and NMR spectroscopic techniques. Applying density functional theory (DFT) at the B3LYP, APFD, PBEPBE, HCTH, TPSSTPSS, and ωB97XD/aug-cc-pVDZ level of theories for the electronic structural properties. In-vitro analysis, molecular docking, molecular dynamic (MD) simulation of the compounds was conducted to investigate the anti-inflammatory potential using COXs enzymes. Docking indicates binding affinity of −9.57, −9.60, −6.77 and −7.37 kcal/mol for DTPS1, DTPS2, Ibuprofen and Diclofenac which agrees with in-vitro assay. Results of MD simulation, indicates sulphonic group in DTPS1 has > 30% interaction with the hydroxyl and oxygen atoms in amino acid residues, but > 35% interaction with the DTPS2. It can be said that the DTPS1 and DTPS2 can induce inhibitory effect on COXs to halt biosynthesis of prostaglandins (PGs), a chief mediator of inflammation and pain in mammals. Communicated by Ramaswamy H. Sarma

Considering the current dramatic and fatal situation due to the high spreading of SARS-CoV-2 infection, there is an urgent unmet medical need to identify novel and effective approaches for prevention and treatment of Coronavirus disease (COVID 19) by re-evaluating and repurposing of known drugs. For this, tomatidine and patchouli alcohol have been selected as potential drugs for combating the virus. The hit compounds were subsequently docked into the active site and molecular docking analyses revealed that both drugs can bind the active site of SARS-CoV-2 3CLpro, PLpro, NSP15, COX-2 and PLA2 targets with a number of important binding interactions. To further validate the interactions of promising compound tomatidine, Molecular dynamics study of 100 ns was carried out towards 3CLpro, NSP15 and COX-2. This indicated that the protein-ligand complex was stable throughout the simulation period, and minimal backbone fluctuations have ensued in the system. Post dynamic MM-GBSA analysis of molecular dynamics data showed promising mean binding free energy 47.4633 ± 9.28, 51.8064 ± 8.91 and 54.8918 ± 7.55 kcal/mol, respectively. Likewise, in silico ADMET studies of the selected ligands showed excellent pharmacokinetic properties with good absorption, bioavailability and devoid of toxicity. Therefore, patchouli alcohol and especially, tomatidine may provide prospect treatment options against SARS-CoV-2 infection by potentially inhibiting virus duplication though more research is guaranteed and secured.

Since the last 4 decades, Bedaquiline has been the first drug discovered as a new kind of anti-tubercular agent and received FDA approval in December 2012 to treat pulmonary multi-drug resistance tuberculosis (MDR-TB). It demonstrates excellent efficacy against MDR-TB by effectively inhibiting mycobacterial ATP synthase. In addition to these apparent assets of Bedaquiline, potential disadvantages of Bedaquiline include inhibition of the hERG (human Ether-à-go-related gene; KCNH2), potassium channel (concurrent risk of cardiac toxicity), and risk of phospholipidosis due to its more lipophilic nature. To assist the effective treatment of MDR-TB, highly active Bedaquiline analogs that display a better safety profile are urgently needed. A structure-based virtual screening approach was used to address the toxicity problems associated with Bedaquiline. Among the virtually screened compound, CID 15947587 had significant docking affinity (− 5.636 kcal/mol) and highest binding free energy (ΔG bind − 85.2703 kcal/mol) towards the Mycobacterial ATP synthase enzyme with insignificant cardiotoxicity and lipophilicity. During MD simulation studies (50 ns), the molecule optimizes its conformation to fit better the active receptor site justifying the binding affinity. The obtained results showed that CID15947587 could be a useful template for further optimizing the MDR-TB inhibitor. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40203-021-00086-x.

The highly infectious disease COVID-19 is induced by SARS-coronavirus 2 (SARS-CoV-2), which has spread rapidly around the globe and was announced as a pandemic by the World Health Organization (WHO) in March 2020. SARS-CoV-2 binds to the host cell's angiotensin converting enzyme 2 (ACE2) receptor through the viral surface spike glycoprotein (S-protein). ACE2 is expressed in the oral mucosa and can therefore constitute an essential route for entry of SARS-CoV-2 into hosts through the tongue and lung epithelial cells. At present, no effective treatments for SARS-CoV-2 are yet in place. Blocking entry of the virus by inhibiting ACE2 is more advantageous than inhibiting the subsequent stages of the SARS-CoV-2 life cycle. Based on current published evidence, we have summarized the different in silico based studies and repurposing of anti-viral drugs to target ACE2, SARS-CoV-2 S-Protein: ACE2 and SARS-CoV-2 S-RBD: ACE2. This review will be useful to researchers looking to effectively recognize and deal with SARS-CoV-2, and in the development of repurposed ACE2 inhibitors against COVID-19.

Mycobacterium tuberculosis (MTB) infection has become a growing health risk as multi-drug resistant strain (MDR-MTB) has emerged worldwide. The development of isoniazid (INH)-resistant M. tuberculosis strains dictate the need to re-design this old drug to create effective analogs against the resistant INH strains. Synthesis and the biological activity of isoniazid and pyridine derivatives were successfully carried out with elaborated characterization by spectral data. Amongst the synthesized compounds; 1 and 2 displayed encouraging antimycobacterial activity with IC50 of 3.2 µM and 1.5 µM against the H37Rv strain. The MIC of test compounds 1 and 2 were also assessed against the 5 drug resistant isolates (FQ-R1, INH-R1, INH-R2, RIF-R1 and RIF-R2) of MTB strains under aerobic conditions and compound 1 [MIC = 3.2 µM for FQ-R1; MIC = 140 µM for INH-R1; MIC = 160 µM for INH-R2; MIC = 2.4 µM towards RIF-R1; MIC = 4.2 µM for RIF-R2] and 2 [MIC = 3.3 µM for FQ-R1; MIC = 170 µM for INH-R1; MIC = 190 µM for INH-R2; MIC = 1.8 µM for RIF-R1; MIC = 8.4 µM for RIF-R2] have shown significant activity at non-cytotoxic concentration in comparison to the standard drug.

Third generation EGFR inhibitor osimertinib was approved as the first-line treatment for EGFR T790M mutation-positive Non-Small Cell Lung Cancer (NSCLC) patients in 2017. However, EGFR tertiary Cys797 to Ser797 (C797S) point mutation emanate rapidly after treatment of osimertinib, which is undruggable mutation to the all existing drugs. In this work, we have reported the novel T790M/C797S-EGFR Tyrosine Kinase inhibitors using BREED based de novo hybridization approach. BREED generates novel inhibitors from structures of known ligands bound to a common target. Among the generated hybridised breed compounds, the top best scorer breed molecules were breed 436, breed 530, breed 450, breed 562 and breed 313. Molecular Dynamics simulation of breed 436 for 10 ns further suggested that docked compound was stable into the pocket of the T790M/C797S-EGFR Tyrosine Kinase. In silico pharmacokinetic predictions of the breed hybridised compounds were within the defined range described for human use. Communicated by Ramaswamy H. Sarma

Third generation EGFR inhibitor osimertinib was approved as the first-line treatment for EGFR T790M mutation-positive Non-Small Cell Lung Cancer (NSCLC) patients in 2017. However, EGFR tertiary Cys797 to Ser797 (C797S) point mutation emanate rapidly after treatment of osimertinib, which is undruggable mutation to the all existing drugs. Recently, EAI045 fourth-generation allosteric EGFR inhibitor has been reported, which binds away from the ATP-binding site and not rely on Cys 797 binding. Here, we are reporting compound ZINC20531199 by virtual based screening studies as allosteric inhibitor to overcome the EGFR T790M/C797S Tyrosine Kinase (TK) mutation problem. Molecular Dynamics simulation for 10 ns further suggested that docked compound ZINC20531199 was stable into the allosteric pocket of the C797S EGFR tyrosine kinase. In silico pharmacokinetic predictions of the virtually screened compounds are within the defined range described for human use. Results indicate that the virtual screened compounds could be potential leads for the further development of new allosteric EGFR T790M/C797S inhibitors to overcome the problem of drug resistance. Communicated by Ramaswamy H. Sarma

Cardiotoxicity is one amongst the adverse effect of Osimertinib delineate in clinical trials and related to escalating doses. To triumph over the drawbacks of Osimertinib, in this study, we tend to delineate the design, synthesis, in vitro biological analysis of a series of novel reversible selective T790M inhibitors with minimal cardiotoxicity. Amongst the virtually sorted compounds; compound 18 and 74 have been located to be the foremost active compounds of the series with IC50 value of 0.88, 0.92 μM in cellular assay and 0.56, 0.62 μM in enzymatic assay, against double mutant L858R/T790M EGFR. Additionally, they showed much less affinity toward wild-type (WT)-EGFR with minimal cardiotoxicity.

In the present research, we report the synthesis and in vitro antimicrobial activity of a new series of novel quinazolino-thiadiazoles as fused pharmacophore (3–20). In general, the results of the in vitro antibacterial activity are encouraging, as out of 18 compounds tested, Compounds 3 and 8 with a 4-chlorophenyl and 4-nitro phenyl at C-2 of thiadiazole and chloromethyl substituent at C-2 of quinazolinone displayed a broad spectrum antimicrobial activity against all the strains, while compounds 13 and 16 again with a 4-chlorophenyl and 4-nitrophenyl at C-2 of thiadiazole and ethyl substituent at C-2 of quinazolinone showed the same potency but with a narrower spectrum (Bacterial and Fungal strains) with MIC values of 62.5 µg/ml. The structures of the compounds were confirmed by IR, 1H NMR, 13C NMR and Mass analysis. It is worth to mention that the combination of two biologically active moieties quinazoline and thiadiazole profoundly influences the biological activity.

COVID-19 caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has threatened the whole world affecting almost 243 million people globally. Originating from China, it has now spread worldwide with USA and India being the two most affected countries which emphasizes the immense potential of the coronaviruses to cause severity in the human population. This study validates the efficacy of some marine antiviral agents to target the viral main protease (Mpro) of SARS-CoV-2 by in silico studies. A total of 14 marine-derived antiviral agents were screened from several databases including PubChem and DrugBank and docked against the crystallised 3D structure of SARS-CoV-2 Mpro. MD simulation of the top two ligands was carried out for 100 ns to validate the protein-ligand stability. Later, their physicochemical, pharmacokinetics, and drug-likeness properties were evaluated and toxicity prediction was performed using eMOLTOX webtool. We found that all the 14 compounds are acting as a good target for Mpro. Among them, avarol and AcDa-1 procured the best docking results with the estimated docking score of −8.05 and −7.74 ​kcal/mol respectively. MD simulation revealed good conformational stability. The docked conformation was visualised and subsequent ligand-amino acid interactions were analysed. Avarol revealed good pharmacokinetic properties with oral bioavailability. The overall finding suggested that these marine compounds may have the potential to be used for the treatment of COVID-19 to tackle this pandemic., Graphical abstract Image 1

Novel chemotherapeutic agents against multidrug resistant-tuberculosis (MDR-TB) are urgently needed at this juncture to save the life of TB-infected patients. In this work, we have synthesized and characterized novel isatin hydrazones 4(a-o) and their thiomorpholine tethered analogues 5(a-o). All the synthesized compounds were initially screened for their anti-mycobacterial activity against the H37Rv strain of Mycobacterium tuberculosis (MTB) under level-I testing. Remarkably, five compounds 4f, 4h, 4n, 5f and 5m (IC50 = 1.9 µM to 9.8 µM) were found to be most active, with 4f (IC50 = 1.9 µM) indicating highest inhibition of H37Rv. These compounds were further evaluated at level-II testing against the five drug-resistant strains such as isoniazid-resistant strains (INH-R1 and INH-R2), rifampicin-resistant strains (RIF-R1 and RIF-R2) and fluoroquinolone-resistant strain (FQ-R1) of MTB. Interestingly, 4f and 5f emerged as the most potent compounds with IC50 of 3.6 µM and 1.9 µM against RIF-R1 MTB strain, followed by INH-R1 MTB strain with IC50 of 3.5 µM and 3.4 µM, respectively. Against FQ-R1 MTB strain, the lead compounds 4f and 5f displayed excellent inhibition at IC50 5.9 µM and 4.9 µM, respectively indicating broad-spectrum of activity. Further, molecular docking, ADME pharmacokinetic and molecular dynamics simulations of the compounds were performed against the DNA gyrase B and obtained encouraging results.

T790M mutation is the most common mechanism of acquired resistance to first-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). To overcome this resistance, 4-anilinoquinazoline-based irreversible inhibitors afatinib, dacomitinib has been developed. However, the clinical application of these irreversible inhibitors is limited due to its narrow selectivity against L858R/T790M mutant EGFR. In an attempt to develop potent and selective EGFR T790M inhibitors, we have designed and synthesized two series of novel acrylamide linked quinazolines. Among them, compounds 2i (IC50 0.171 µM) and 11h (IC50 0.159 µM) were identified as potent compounds, which displayed selective and potent anti-proliferative activity on gefitinib-resistant cell line NCI-H1975 as compared to the gefitinib and WZ4002 in cellular assay. Furthermore, a molecular dynamic simulation of 11h was carried out to assess the stability to form a complex with the L858R/T790M EGFR Kinase domain, which demonstrated that complex was stable for the 100 ns and form strong crucial covalent binding contacts with the thiol group of Cys797 residue. Finally, satisfactory in silico pharmacokinetics properties of 2i, 11h and 11i compounds were predicted. The synthesized compounds were also evaluated for in vitro cytotoxic activity/hepatotoxicity against HepG2 cell line through MTT assay. The results revealed that compounds exhibited lower cytotoxicity to HepG2 cells.

Nowadays, hybrid drugs containing two or more covalently linked known potential pharmacophores are designed to simultaneously modulate multiple targets of multifactorial diseases to overcome the side effects associated with a single drug. In this review, an overview of the design strategies employed by various scientists over the past 20 years has been presented. The overview includes the synthesis of different chemical structure-based anticancer hybrids using molecular hybridization techniques. To tackle one of the world's most devastating diseases such as cancer, researchers have exploited the molecular hybridization (MH) technique to synthesize different anticancer hybrids, which include hybrids based on azole, camptothecin, chalcone, pyrrolobenzodiazepine (PBD), coumarin, colchicine, platinum, and some miscellaneous structures. The selection of two or more moieties for generating the hybrid drug is generally aided by the observed (or anticipated) synergistic or additive pharmacological activities of each single moiety. This eventually leads to the identification of novel and better active chemical entities with a superior profile as compared to the parent moieties. In addition to the design strategies, this review also highlights the structure–activity relationship (SAR), mechanism of action, and key features of the synthesized anticancer hybrids.

The polyelectrolyte complexes (PECs) are versatile formulations formed by electrostatic interactions between oppositely charged biopolymers. PECs have been investigated widely by the researchers to explore the virtues of this formulation viz. high biocompatibility, excellent biodegradability, low toxicity, cost-effective, environment-friendly, and energy-efficient production. The prime object of the present review is to present the prominent features of PECs including mechanism of PEC formation, structural models of PECs, interactions involved in PEC formation, steps involved in PEC fabrication, factors affecting the formation of PECs and applications of PECs. The patents pertaining to PECs have briefly been tabulated as well.

Antimalarial drugs play a crucial role in the treatment and cure of malaria. Electrochemical sensors have been the subject of extensive research in the field of drug analysis since many decades, and yet seem to project great potential for the future. The present review explores the basic strategies and recent developments in the electroanalysis of antimalarial drugs in various matrices. A discussion of the commonly used electroanalytical methods for drug assays is briefly discussed. The methods have been critically analysed highlighting their analytical performance and limitations. Nanomaterials, conducting polymers and presence of surfactants made significant contributions to voltammetric determination of antimalarial drugs suggesting promising future for use of chemically-modified electrode based sensors for the detection. Future progress in quantification of these drugs in biological fluids is expected to drastically improve the applicability of electrochemical methods for routine clinical analysis.

In the course of our search for new antitumor agents for breast cancer, novel flavone derivatives were synthesized, characterized and examined for their antitumor activities against breast cancer cell lines. In initial screening, analogs 7a [3-(5-amino-1,3,4-thiadiazol-2-yl)methoxy-2-phenyl-4H-chromen-4-one] and 7b [3-(5-amino-1,3,4-thiadiazol-2-yl)methoxy-2-(4-methoxyphenyl)-4H-chromen-4-one] were found to be effective against the estrogen receptor negative cell line (MDA-MB 453), which was followed by their evaluation in five dose assays. In addition, mechanistic studies of 7a and 7b were performed by cytometric analysis and electrophoretic studies and it was observed that apoptosis is a mechanism of cell death, confirmed morphologically by acridine orange/ethidium bromide double staining and TUNEL analysis. Further in vivo evaluation of the anti-tumor activity of compound 7a and 7b by Ehrlich Ascites Carcinoma (EAC) model and related studies confirms the anti-breast cancer potential of flavonoid analogs.

A series of novel quinazoline derivatives were synthesized, virtually screened through different filters and evaluated for their anticonvulsant activity against electrically and chemically induced seizures, compared with that of the standard drugs methaqualone and sodium valproate. Compound 48, 3-(2-aminophenyl)-7-chloro-2-phenylquinazolin-4(3H)-one, was found to be the most potent compound of the series accompanied by relatively low neurotoxicity and low toxicity in the median lethal dose test as compared with the reference drugs. The obtained results showed that compounds 12, 48, 49 and 50 could be useful templates for future design, optimization, and investigation to construct more active analogs.

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. A library of 6,7-dimethoxy quinazoline was prepared using a ligand based drug design approach and passed through different filters of virtual screening such as a docking study and Lipinski's rule. Twenty virtually screened compounds were synthesized and investigated against VEGFR-2 kinase and human umbilical vein endothelial cells (HUVEC) in vitro. Virtually screened compound 47 having 4-chlorophenyl-1,3,4-thiadiazole substitution at 3rd position of 6,7-dimethoxy-2-phenylquinazolin-4-(3H)-one exhibited the most promising activity, with IC50 values of 3.8 nm and 5.5 nm against VEGFR-2 tyrosine kinase and the HUVEC cell line. Docking simulation supported the initial pharmacophoric hypothesis and suggested a common mode of interaction at the ATP-binding site of VEGFR-2 demonstrating that compound 47 is a potential agent for cancer therapy that deserves further research.

The present study reports the synthesis of NiO–ZrO2 nanocomposites followed by their characterization using X-ray powder diffraction, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. A new chemically modified glassy carbon electrode was fabricated based on the synthesized nanocomposite and used as a highly sensitive electrochemical sensor for the determination of efavirenz, an anti-HIV drug. The modification increased the effective surface area of the sensor ten times in comparison to the bare glassy carbon electrode. Cyclic voltammograms revealed that the modified electrode exhibits excellent electrocatalytic activity towards oxidation of the drug. The current displayed a wide linear response ranging from 0.01 to 10 μM with a detection limit of 1.36 nM. The effect of interferents on the peak current response was studied. The electrode displayed advantages such as simple preparation, appreciable stability, reproducibility and high sensitivity. The feasibility of the proposed method was successfully demonstrated by determining efavirenz in commercial pharmaceutical formulations and human urine samples.

In the present study, a series of imidazo[2,1-b][1,3,4]thiadiazole derivatives 5(a–j) were synthesized and characterized by IR, 1H NMR, 13C NMR and mass spectral technique. The compounds were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv strain by using Alamar Blue susceptibility test as part of the TAACF TB screening program under direction of the US National Institutes of Health, the NIAID division. Among the tested compounds, 2-(1-methyl-1H-imidazol-2-yl)-6-(4-nitrophenyl)imidazo[2,1-b][1,3,4]thiadiazole (5f) has shown the highest (98%) inhibitory activity with MIC of 3.14 μg/ml as compared to other tested compounds. Further, some potent compounds were also assessed for their cytotoxic activity against a mammalian Vero cell line using MTT assay. The results reveal that these compounds exhibit anti-tubercular activity at non-cytotoxic concentrations.

A series of 1-methyl-N-((substituted-phenylmethylidene)-1H-benzimidazol-2-amines (4a-4g) were prepared via the formation of 1-methyl-1H-benzimidazol-2-amine (3), which was pre- pared by the cycloaddition of o-phenylenediamine (1) with cyanogen bromide in the presence of aqueous base followed by N-methylation with methyl iodide in the presence of anhydrous potas- sium carbonate in dry acetonitrile. Moreover, the four-membered b-lactam ring was introduced by the cycloaddition of 4a-4g and chloroacetyl chloride in the presence of triethylamine catalyst to give 3-chloro-1-(1-methyl-1H-benzimidazol-2-yl)-(4 0 -substituted)-phenylazetidin-2-one 5a-5g .A total of 14 compounds were synthesized and characterized by IR, 1 H NMR, 13 C NMR and Mass spectral technique, in addition they were evaluated for anti-bacterial and cytotoxic properties. Among the chemicals tested 4a, 4b, 5a, 5b, 5g exhibited good antibacterial activity and 5f, 5g shown good cytotoxic activity in vitro. a 2011 Production and hosting by Elsevier B.V. on behalf of King Saud University.

Various substituted carbazolo–thiazoles (compounds 6a–6o) were synthesized in good yields using a molecular hybridization approach. The synthesized compounds were evaluated for their in vitro anti-tubercular activity against Mycobacterium tuberculosis H37Rv strain at the National Institute of Allergy and Infectious Diseases (Bethesda, MD, USA). Among the tested series, compound 6c (minimum inhibitory concentration 21 μM) showed the most promising anti-mycobacterial activity. Brief structure–activity relationship studies showed that the electron-donating groups (OCH3 and OH), particularly on the phenyl ring of the thiazole motif, had a positive correlation with the anti-mycobacterial activity. In addition, they displayed low cytotoxicity against a mammalian Vero cell line using the MTT assay, thereby having a high therapeutic index. This study shows the importance of molecular hybridization and the scope for the development of carbazole–thiazole compounds as potential anti-mycobacterial agents.

A novel 3-(substituted benzylideneamino)-7-chloro-2-phenyl quinazoline-4(3 H )-one ( 7 – 27 ) has been synthesized and characterised by IR, 1 H NMR, 13 C NMR spectroscopy, and elemental analysis. We changed the methodology for the synthesis of 3-amino 7-chloro-2-phenyl quinazolin-4(3 H )-one 6 to fusion reaction at 250 °C, instead of using solvent, to avoid the problem of ring opening, which is commonly observed while synthesizing quinazolines from benzoxazinone. NCI selected, 7-chloro-3-{[(4-chlorophenyl) methylidene] amino}-2-phenylquinazolin-4(3 H )-one 12 , with GI 50 value of −5.59 M, TGI value of −5.12 M, and LC 50 value of −4.40 M showed remarkable activity against CNS SNB-75 Cancer cell line. Rational approach and QSAR techniques enabled the understanding of the pharmacophoric requirement for 2,3,7-tri substituted quinazoline derivatives to inhibit EGFR-tyrosine kinase as antitumor agents and could be used as an excellent framework in this field that may lead to discovery of potent anti tumor agent.

With the aim of producing new biologically active compounds, a series of New Pyridine Imidazo [2,1b]-1,3,4-thiadiazole derivatives 4(a–k) were synthesized. All the compounds were characterized via IR, 1H-NMR and Mass spectral studies. The antimicrobial activity of newly synthesized compounds against various bacteria; Bacillus pumillus, Staphylococcus aureus, Vibrio cholera, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, and fungi; Candida albicans were evaluated. Among the compounds tested, 4(a), 4(b), 4(f), 4(h) and 4(k) exhibited good antimicrobial activity while others responded moderately with reference to standard drugs ampicillin and amphotericin B.

Pentacyclic Triterpenoids (PTs) and their analogues as well as derivatives are emerging as important drug leads for various diseases. They act through a variety of mechanisms and a majority of them inhibit the nuclear factor kappa-beta (NF-κB) signaling pathway. In this study, we examined the effects of the naturally occurring PTs on IκB kinase-β (IKKβ), which has great scientific relevance in the NF-κB signaling pathway. On virtual screening, 109 PTs were screened through the PASS (prediction of activity spectra of substances) software for prediction of NF-κB inhibitory activity followed by docking on the NEMO/IKKβ association complex (PDB: 3BRV) and testing for compliance with the softened Lipinski's Rule of Five using Schrodinger (LLC, New York, USA). Out of the projected 45 druggable PTs, Corosolic Acid (CA), Asiatic Acid (AA) and Ursolic Acid (UA) were assayed for IKKβ kinase activity in the cell free medium. The UA exhibited a potent IKKβ inhibitory effect on the hotspot kinase assay with IC50 of 69 μM. Whereas, CA at 50 μM concentration markedly reduced the NF-κB luciferase activity and phospho-IKKβ protein expressions. The PTs tested, attenuated the expression of the NF-κB cascade proteins in the LPS-stimulated RAW 264.7 cells, prevented the phosphorylation of the IKKα/β and blocked the activation of the Interferon-gamma (IFN-γ). The results suggest that the IKKβ inhibition is the major mechanism of the PTs-induced NF-κB inhibition. PASS predictions along with in-silico docking against the NEMO/IKKβ can be successfully applied in the selection of the prospective NF-κB inhibitory downregulators of IKKβ phosphorylation.

A quantitative structure activity relationship study of 66 molecules was performed using MLR(Multiple Linear Regression) and PCR (Principal component Analysis) of aldose reductase by flavonoids compounds.Various descriptors, topological indices were used to characterize flavonoids molecules.In the developed model MLR is giving vary significant results wheras PCR has revealed some important information. Keywords: Flavonoids, aldose reuctase, QSAR, Multiple Linear Regression, Principle Component Regression

A new stability-indicating reversed-phase high-performance thin-layer chromatographic (RP-HPTLC) method for densitometric analysis of thiocolchicoside was developed and validated. The chromatograms were developed using aluminum plates pre-coated with silica gel 60 RP-18 F254S as a stationary phase and methanol : water (70 : 30 v/v) as a mobile phase. The compact band for thiocolchicoside was observed at R f value of 0.60 ± 0.02 at an absorption wavelength of 377 nm. The linear regression data for the calibration plots (r (2) = 0.9984) was found with respect to peak area in the concentration range of 100-600 ng per band. The limit of detection (LOD) and limit of quantification (LOQ) were 9.77 ng and 29.63 ng, respectively. The drug was exposed to acidic and alkaline hydrolysis, oxidation, photo degradation, and dry heat conditions. The peaks of degradation products were well-resolved from the peak of the standard drug with significantly different R f values. Statistical analysis proved that the established RP-HPTLC method is reproducible, selective, and accurate for the determination of thiocolchicoside in its formulations. The method can effectively separate the drug from its degradation products, and it can be considered as stability-indicating assay.

Pharmacophore modeling studies were undertaken for a series of quinoline derivatives as VEGFR-2 tyrosine kinase inhibitors. A five-point pharmacophore with two hydrogen bond acceptors (A), one hydrogen bond donor (D), and two aromatic rings (R) as pharmacophore features was developed. The pharmacophore hypothesis yielded a statistically significant 3D-QSAR model, with a correlation coefficient of r 2 = 0.8621 for training set compounds. The model generated showed excellent predictive power, with a correlation coefficient of q 2 = 0.6943 and for a test set of compounds. Furthermore, the structure–activity relationships of quinoline derivatives as VEGFR-2 tyrosine kinase inhibitors were elucidated and the activity differences between them discussed. Docking studies were also carried out wherein active and inactive compounds were docked into the active site of the VEGFR-2 crystal structure to analyze drug-receptor interactions. Further we analyzed all the compounds for Lipinski’s rule of five to evaluate drug likeness and established in silico ADME parameters using QikProp. The results provide insights that will aid the optimization of these classes of VEGFR-2 inhibitors for better activity, and may prove helpful for further lead optimization and virtual screening.

In an attempt to find a new class of antimicrobial agents, a series of novel N ′-(5 or 7 substituted-2-oxoindolin-3-ylidene)benzofuran-2-carbohydrazides 3 ( a – p ) were synthesized by reacting benzofuran-2-carbohydrazide 1 with 5 and 7 substituted-isatins 2 ( a – p ). The synthesized compounds were confirmed by melting point, IR, 1 H NMR, 13 C NMR and mass spectroscopy. All the synthesized compounds were screened for antimicrobial activity among the tested series, 3o exhibited excellent antibacterial activity against Escherichia coli and Pseudomonas vulgaris while 3p against Bacillus subtilis , E. coli and P. vulgaris (31.25 μg/mL) when compared with standards. Similarly 3o and 3p showed significant antifungal activity (31.25 μg/mL) when compared to fluconazole against Aspergillus niger .

Epidermal growth factor receptor (EGFR) protein tyrosine kinases (PTKs) are known for its role in cancer. Quinazoline have been reported to be the molecules of interest, with potent anticancer activity and they act by binding to ATP site of protein kinases. ATP binding site of protein kinases provides an extensive opportunity to design newer analogs. With this background, we report an attempt to discern the structural and physicochemical requirements for inhibition of EGFR tyrosine kinase. The k-Nearest Neighbor Molecular Field Analysis (kNN-MFA), a three dimensional quantitative structure activity relationship (3D- QSAR) method has been used in the present case to study the correlation between the molecular properties and the tyrosine kinase (EGFR) inhibitory activities on a series of quinazoline derivatives. kNNMFA calculations for both electrostatic and steric field were carried out. The master grid maps derived from the best model has been used to display the contribution of electrostatic potential and steric field. The statistical results showed significant correlation coefficient r(2) (q(2)) of 0.846, r(2) for external test set (pred_r2) 0.8029, coefficient of correlation of predicted data set (pred_r(2)se) of 0.6658, degree of freedom 89 and k nearest neighbor of 2. Therefore, this study not only casts light on binding mechanism between EGFR and its inhibitors, but also provides hints for the design of new EGFR inhibitors with observable structural diversity.

In this paper, an attempt was made to develop a quantitative structure–activity relationship (2D and 3D QSAR) and molecular docking studies on a series of quinazoline derivatives acting as protein tyrosine kinases (EGFR) inhibitors. 2D QSAR was performed using multiple linear regression (MLR), principal component regression (PCR) and partial least squares regression (PLS) methods. Among these three methods, multiple linear regression (MLR) method has come out with a very promising result as compared to other two methods. According to Model-1 by MLR anticancer activity of quinazoline derivatives were influenced by individual (H-donor count, and XlogP) and alignment independent descriptor (T_C_Br_1, T_2_O_1 and T_2_N_7) help in understanding the effect of substituent at different position of quinazolines. The contribution plot of steric and electrostatic field interactions generated by 3D-QSAR shows interesting results in terms of internal and external predictability. Molecular field analysis was applied for the generation of steric and electrostatic descriptors based on aligned structures. Steric and electrostatic field effects are discussed in the light of contribution plot generated. Finally, molecular docking analysis was carried out to better understand the interactions between EGFR target and inhibitors in this series. Hydrophobic and hydrogen bond interactions lead to identification of active binding sites of EGFR protein in the docked complex. The present study is more versatile than the earlier reported methods. Hence the model proposed in this work can be employed to design new derivatives of quinazoline with specific tyrosine kinase (EGFR) inhibitory activity.

A series of 1,3,4-thiadiazole derivatives of 2-(4-formyl-2-methoxyphenoxy) acetic acid ( 6a – s ) were synthesized by cyclization of carboxylic acid group of 2-(2-methoxy-4-(3-oxo-3-substituted phenylprop-1-enyl)phenoxy) acetic acid ( 4a – s ) with thiosemicarbazide in the presence of POCl 3 or PPA. The structures of the compounds were confirmed by IR, 1 H NMR and mass analysis. All the compounds have been evaluated in vitro for their antimicrobial activities against several strains of microbes and show significant activity.