Isolation and characterization of ACE-I inhibitory peptides from ribbonfish for a potential inhibitor of the main protease of SARS-CoV-2: An in silico analysis.

Recently, multifunctional fish peptides (FWPs) have gained a lot of attention because of their different biological activities. In the present study, three angiotensin-I converting enzyme (ACE-I) inhibitory peptides [Ala-Pro-Asp-Gly (APDG), Pro-Thr-Arg (PTR), and Ala-Asp (AD)] were isolated and characterized from ribbonfish protein hydrolysate (RFPH) and described their mechanism of action on ACE activity. As per the results, peptide PTR showed ≈ 2 and 2.5-fold higher enzyme inhibitory activity (IC50 = 0.643 ± 0.0011 µM) than APDG (IC50 = 1.061 ± 0.0127 µM) and AD (IC50 = 2.046 ± 0.0130 µM). Based on experimental evidence, peptides were used for in silico analysis to check the inhibitory activity of the main protease (PDB: 7BQY) of SARS-CoV-2. The results of the study reveal that PTR (-46.16 kcal/mol) showed higher binding affinity than APDG (-36.80 kcal/mol) and AD (-30.24 kcal/mol) compared with remdesivir (-30.64 kcal/mol). Additionally, physicochemical characteristics of all the isolated peptides exhibited appropriate pharmacological properties and were found to be nontoxic. Besides, 20 ns molecular dynamic simulation study confirms the rigid nature, fewer confirmation variations, and binding stiffness of the peptide PTR with the main protease of SARS-CoV-2. Therefore, the present study strongly suggested that PTR is the perfect substrate for inhibiting the main protease of SARS-CoV-2 through the in silico study, and this potential drug candidate may promote the researcher for future wet lab experiments.

Identification of benzothiazole-rhodanine derivatives as α-amylase and α-glucosidase inhibitors: Design, synthesis, in silico, and in vitro analysis.

A novel series of benzothiazole-rhodanine derivatives (A1-A10) were designed and synthesized, with the aim of developing possible antidiabetic agents and the spectral characterization of these compounds was done using infrared spectroscopy (IR), proton-nuclear magnetic resonance (1 H-NMR), carbon-nuclear magnetic resonance (C13 -NMR), and high resolution mass spectroscopy (HR-MS) techniques. In vitro hypoglycemic potential of the compounds was evaluated by performing α-amylase and α-glucosidase enzyme inhibitory assays. In addition, these compounds were subjected to in silico analysis. Based on the results, compounds A5, A6, and A9 displayed good activity in comparison with the standard acarbose. Based on Lineweaver-Burk plots, it was concluded that compounds A5 and A9 displayed competitive type of enzyme inhibition. Molecular dynamic simulations were conducted to evaluate the stability of the ligand-protein complex by the calculation of the root mean square deviation, root means square fluctuation, and solvent accessible surface area.

Molecular docking, antiproliferative and anticonvulsant activities of swertiamarin isolated from Enicostemma axillare.

Present study aimed for molecular docking, antiproliferative and anticonvulsant activities of swertiamarin isolated from the successive methanol extract of Enicostemma axillare. Molecular docking of swertiamarin on telomerase targets (PDB ID: 5UGW, 3DU6 and 4ERD), followed by antiproliferative activity on HEp2 and HT-29 cells by MTT and SRB assays. Also tested for anticonvulsant activity by pentylenetetrazole (PTZ, 80 mg/kg bw) induced convulsant. Molecular docking study predicted good total score of the swertiamarin with the selected targets. Swertiamarin possesses antiproliferative activity on HEp-2 and HT-29 cells with lower CTC50 values. It also served as significant anticonvulsant agent with prolonged onset and reduced duration of the seizures. These results confirm that swertiamarin exhibited potential antiproliferative and anticonvulsant activities.

Synthesis, molecular modeling and BACE-1 inhibitory study of tetrahydrobenzo[b] pyran derivatives.

ß-Secretase (BACE1) has been broadly documented as one of the possible therapeutic targets for the treatment of Alzheimer's disease. In this paper, we report the synthesis and the for ß-secretase (BACE-1) inhibitory activity of new series of tetrahydrobenzo [b] pyran derivatives. One-pot synthesis of tetrahydrobenzo [b] pyrans was carried out by condensing aromatic aldehyde, malononitrile and 1,3-cyclohexanedione using ionic liquid 1-butyl-3-methyl imidazolium chloride ([bmIm]Cl-) in aqueous alcohol media. The addition of alcohol and water in the ratio of 1:2 keeps all the reactants in solution which facilitates the reaction and makes the product formation very easy. The synthesized compounds were subjected to BACE1 inhibition assay and six compounds, 4d, 4e, 4f, 4h, 4i, and 4p have shown significant IC50 values at micromolar level. Among these six active compounds, 4e was a potential inhibitor with its IC50 value in nanomolar range. All the synthesized compounds were docked onto the active site of ß-Secretase enzyme.

Pharmacophore mapping, molecular docking, chemical synthesis of some novel pyrrolyl benzamide derivatives and evaluation of their inhibitory activity against enoyl-ACP reductase (InhA) and Mycobacterium tuberculosis.

In an effort to produce new lead antimycobacterial compounds, herein we have reported the synthesis of a sequence of new pyrrolyl benzamide derivatives. The new chemical entities were screened to target enoyl-ACP reductase enzyme, which is one of the key enzymes of M. tuberculosis that are involved in type II fatty acid biosynthetic pathway. Compound 3q exhibited H-bonding interactions with Tyr158, Thr196 and co-factor NAD+ that binds the active site of InhA. All the pyrrolyl benzamide compounds were evaluated as inhibitors of M. tuberculosis H37Rv as well as inhibitors of InhA. Among them, few representative compounds were tested for mammalian cell toxicity on the human lung cancer cell-line (A549) and MV cell line that presented no cytotoxicity. Five of these compounds exhibited a good activity against InhA.

Novel quinoxalinyl chalcone hybrid scaffolds as enoyl ACP reductase inhibitors: Synthesis, molecular docking and biological evaluation.

We report herein, first ever synthesis of series of novel differently substituted quinoxalinyl chalcones using Claisen Schmidt condensation, its molecular docking studies, and potential to be good anti-microbial, anti-tubercular and anti-cancer agents. The antimicrobial studies were carried out against Staphylococcus aureus, Escherichia coli and Candida albicans using disc diffusion procedure. The selected chalcones were tested for anti-cancer and cytotoxicity activity against MCF-7 cancer cell line using MTT assay method. All the synthesized compounds were screened for in vitro anti-tubercular screening against MtbH37RV strains by Alamar blue dye method. These results were compared with molecular docking studies carried out on Mycobacterium tuberculosis enzyme enoyl ACP reductase using Surflex-Dock program that is interfaced with Sybyl-X 2.0. SAR analysis for antimicrobial and antitubercular activity has also been proposed.

3,4-Dihydropyrimidinone-coumarin analogues as a new class of selective agent against S. aureus: Synthesis, biological evaluation and molecular modelling study.

Bacterial infections are increasingly difficult to combat as bacteria evolve resistance to antibiotic drugs and have severely compromised the arsenal of antibiotic drugs. On the other hand matrix metalloproteinases (MMPs) play a fundamental role in inflammation and extracellular matrix degradation in physiological and pathological conditions. In search of potent antibiotic, taking coumarin and dihydropyrimidinone as lead compound, a green, eco-friendly and efficient protocol has been developed and synthesized the dihydropyrimidin-2(1H)-one/thione derivatives of coumarin 3/4 from substituted 4-formylcoumarins 2 and ethylacetoacetate using urea/thiourea in the presence of catalytic amount of ceric ammonium nitrate is reported. All the synthesized compounds were evaluated for their antibacterial activity against four bacterial strains by broth dilution method. The tested compounds have exhibited promising in vitro potency with low MIC values against the drug susceptive S. aureus strain with low MIC values ranging from 0.2 to 6.25µg/mL. The in vivo anti-inflammatory potency of 3a-e and 4a-e by gelatin zymography is comparable to that of tetracycline. Molecular docking study performed for all the synthesized compounds with S. aureus DNA gyrase and results obtained were quite promising.

Chemical synthesis and in silico molecular modeling of novel pyrrolyl benzohydrazide derivatives: Their biological evaluation against enoyl ACP reductase (InhA) and Mycobacterium tuberculosis.

In efforts to develop new antitubercular agents, we report here the synthesis of a series of novel pyrrole hydrazine derivatives. The molecules were evaluated against inhibitors of InhA, which is one of the key enzymes involved in type II fatty acid biosynthetic pathway of the mycobacterial cell wall as well as inhibitors of Mycobacterium tuberculosis H37Rv. The binding mode of compounds at the active site of enoyl-ACP reductase was explored using the surflex-docking method. The model suggests one or two H-bonding interactions between the compounds and the InhA enzyme. Some compounds exhibited good activities against InhA in addition to promising activities against M. tuberculosis.

One pot Click chemistry: A three component reaction for the synthesis of 2-mercaptobenzimidazole linked coumarinyl triazoles as anti-tubercular agents.

2-Propargylthiobenzimidazole 1, 4-bromomethyl coumarins/1-aza-coumarins 2/3 and sodium azide have been reacted in one pot under Click chemistry conditions to give exclusively 1,4-disubstituted triazoles 5a-n. Anti-tubercular assays against M. tuberculosis (H37Rv) coupled with in silico molecular docking studies indicated that dimethyl substituents 5c and 5d showed promising activity with higher C-score values.

Benzothiazole derivatives as p53-MDM2 inhibitors: in-silico design, ADMET predictions, molecular docking, MM-GBSA Assay, MD simulations studies.

Breast cancer stands as the most prevalent malignancy among the female populace. One of the pivotal domains in the therapeutic landscape of breast cancer revolves around the precise targeting of the p53-MDM2 inhibitory pathway. The advent of p53-MDM2 inhibition in the context of developing treatments for breast cancer marks a significant stride. In the quest for enhancing the efficacy of p53-MDM2 inhibition against breast cancer, a new series of benzothiazole compounds (B1-B30) was designed through in-silico methodologies in the present work. Using Schrodinger Maestro, the compounds underwent molecular docking assessments against the p53-MDM2 target (PDB: 4OGT). Compared to reference compounds, B25 and B12 exhibited notably elevated glide scores. Extensive in-silico studies, including ADMET and toxicity evaluations, were performed to predict pharmacokinetics, drug likeness, and toxicity. All compounds adhered to Lipinski criteria, signifying favorable oral drug properties. The MM-GBSA analysis indicated consistent binding free energies. Molecular dynamics simulations for B25 over 200 ns assessed complex stability and interactions. In summary, these compounds exhibit potential for future cancer therapy medication development.Communicated by Ramaswamy H. Sarma.

Green, unexpected synthesis of bis-coumarin derivatives as potent anti-bacterial and anti-inflammatory agents.

A green and efficient protocol has been developed and a series of coumarin based pyrano[3,2-c]chromene derivatives (2) have been synthesized using multi-component reaction (MCR) approach. Unexpected 3-coumarinyl-3-pyrazolylpropanoic acids (3) and C4-C4 chromenes (5) have been isolated instead of expected product 4 by the reaction of compound (2) in formic acid at 90 °C for about 4-5 h and at 130 °C for about 8-10 h respectively. Further, C4-C4chromenes (5) formation was confirmed by intramolecular cyclization of compounds (3). These compounds were screened for their biological activities and most of them exhibited promising antibacterial activity. The anti-inflammatory assay was evaluated against HRBC membrane stabilization method and the compounds exhibit excellent anti-inflammatory activity. Molecular docking study has been performed for all the synthesized compounds with Klebsiella pneumoni aeacetolactate synthase and results obtained are quite promising.

Synthesis, biological evaluation and in silico molecular modeling of pyrrolyl benzohydrazide derivatives as enoyl ACP reductase inhibitors.

In efforts to develop lead anti-TB compounds, a novel series of 19 pyrrolyl benzohydrazides were synthesized and screened to target enoyl-ACP reductase enzyme, which is one of the important enzymes involved in type II fatty acid biosynthetic pathway of M. tuberculosis. Pharmacophores were constructed using GALAHAD to generate alignment of data sets and calculated by Pareto ranking. The pharmacophore features were then filtered by Surflex-dock study using enoyl ACP reductase from M. tuberculosis. Compounds 5b and 5d showed H-bonding interactions with Tyr158, Thr196 and co-factor NAD+ that fitted well within the binding pocket of InhA. All the synthesized compounds were screened for preliminary antibacterial activities against Gram-positive S. aureus and Gram-negative E. coli and M. tuberculosis H37Rv to evaluate their antitubercular activities. Some representative compounds were further tested for mammalian cell toxicity using human lung cancer cell-line (A549) that was found to be nontoxic. These compounds exhibited moderate inhibition activities against InhA.

Design, synthesis and pharmacological analysis of 5-[4'-(substituted-methyl)[1,1'-biphenyl]-2-yl]-1H-tetrazoles.

In the present paper 5-[4'-({4-[(4-aryloxy)methyl]-1H-1,2,3-triazol-1-yl}methyl)[1,1'-biphenyl]-2-yl]-1H-tetrazoles (5a-g) and [2'-(1H-tetrazol-5-yl)[1,1'-biphenyl]-4-yl]methyl-substituted-1-carbodithioates (11h-q) have been designed and synthesized. These compounds were subjected to docking (against AT1 receptor protein enzyme in complex with Lisinopril), in vitro angiotensin converting enzyme inhibition, anti-proliferative, anti-inflammatory screening (through egg albumin denaturation inhibition and red blood cell membrane stabilization assay) and finally anti-fungal activity analyses. Some of the compounds have shown significant pharmacological properties.

Synthesis, characterization and molecular docking studies of substituted 4-coumarinylpyrano[2,3-c]pyrazole derivatives as potent antibacterial and anti-inflammatory agents.

A green, eco-friendly and efficient protocol has been developed and synthesized a series of coumarin based pyrano[2,3-c]pyrazole derivatives (3) by multi-component reaction (MCR). Unexpected 3-coumarinyl-3-pyrazolylpropanoic acids (4) have been isolated by the reaction of compound (3) in acidic conditions. Further, intramolecular cyclization of compounds (4) leads to C4C4 chromons (9) and these compounds were screened for their biological activities using array of techniques. Most of the compounds exhibited promising antibacterial activity, in particular Gram-positive bacteria. The anti-inflammatory assay was evaluated against protein denaturation as well as HRBC membrane stabilization methods and compounds exhibit excellent anti-inflammatory activity in both methods. Molecular docking study has been performed for all the synthesized compounds with S. aureus dihydropteroate synthetase (DHPS) and results obtained are quite promising.

Design and synthesis of novel phenyl -1, 4-beta-carboline-hybrid molecules as potential anticancer agents.

A series of beta-carbolines with other heterocycles linked by phenyl ring has been designed and synthesized. The key intermediates 3 and 5 were synthesized by condensing tryptamine and teraldehyde via Pictet- Spengler method. All the newly synthesized compounds were tested for their anticancer activity against sixty human cell lines at NCI. The five dose results of compounds 3 and 7a showed enhancement of anticancer activity (GI50 values range from 1.00 to 7.10 µM) against all the cell lines in comparison with some of earlier molecules. In addition to this protein binding and CT-DNA intercalation studies showed molecules are highly potential. The molecular docking studies, which support the multiple mode of interaction with DNA, moreover the synthesized compounds 3 and 7a are more potential and possess drug -like nature.

Tetrazolylmethyl quinolines: Design, docking studies, synthesis, anticancer and antifungal analyses.

A new series of 2,5 and 1,5-regioisomers of the tetrazolyl group viz., 3-[(5-benzyl/benzylthio-2H-tetrazol-2-yl) methyl]-2-chloro-6-substituted quinoline 6h-q and 3-[(5-benzyl/benzylthio-1H-tetrazol-1-yl) methyl]-2-chloro-6-substituted quinolines 7h-q were synthesized. Docking studies of all these compounds with DNA as target using PDB: 1AU5 and 453D revealed that the compounds 6h and 6i act as covalent cross linker on the DNA helix of the former and intercalate the latter both with higher C score values. Another set of docking studies in the active pocket of dihydrofolate reductase and N-myristoyl transferase as targets to assess antifungal activity revealed that compounds 6k, 6l, 6p and 7q (with bromo and fluro substituents) showcases different binding modes and hydrogen bonding. Further, the compounds were screened for anticancer activity (primary cytotoxicity) against NCI-60 Human tumor cell line at a single high dose (10-5 M) concentration assay. Among the tested compounds, 6h has shown 99.28% of GI against Melanoma (SK-MEL-5) and compound 6i has shown 97.56% of GI against Breast Cancer (T-47D). Further, in vitro antifungal assay against A. fumigatus and C. albicans for these compounds 6h-q and 7h-q revealed potential to moderate activities as compared to the standard.

Pyrrolyl Pyrazoline Carbaldehydes as Enoyl-ACP Reductase Inhibitors: Design, Synthesis and Antitubercular Activity.

INTRODUCTION: In efforts to develop new antitubercular (anti-TB) compounds, herein we describe cytotoxic evaluation of 15 newly synthesized pyrrolyl pyrazoline carbaldehydes. METHOD & MATERIALS: Surflex-Docking method was used to study binding modes of the compounds at the active site of the enzyme enoyl ACP reductase from Mycobacterium tuberculosis (M. tuberculosis), which plays an important role in FAS-II biosynthetic pathway of M. tuberculosis and also it is an important target for designing novel anti-TB agents. RESULTS: Among the synthesized compounds, compounds 4g and 4i showed H-bonding interactions with MET98, TYR158 and co-factor NAD+, all of which fitted well within the binding pocket of InhA. Also, these compounds have shown the same type of interaction as that of 4TZK ligand. The compounds were further evaluated for preliminary anti-TB activities against M. tuberculosis H37Rv strain. CONCLUSION: Some compounds were also screened for their mammalian cell toxicity using human lung cancer cell-line (A549) that was found to be nontoxic.

Synthesis, antimycobacterial screening and ligand-based molecular docking studies on novel pyrrole derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties.

We report here the synthesis, antibacterial and antitubercular evaluation of 61 novel pyrrolyl derivatives bearing pyrazoline, isoxazole and phenyl thiourea moieties. Molecular docking was carried out on enoyl ACP reductase from Mycobacterium tuberculsosis using Surflex-Dock, which is one of the key enzymes involved in type II fatty acid biosynthetic pathway of Mycobacterium tuberculosis, an attractive target for designing novel antitubercular agents. Docking analysis of the crystal structure of ENR performed using Surflex-Dock in Sybyl-X 2.0 software indicates the occupation of substituted pyrrolyl derivatives into hydrophobic pocket of InhA enzyme. Compounds 9b and 9d exhibited the highest antitubercular activity almost close to isoniazid (0.4 µg/mL) with a MIC value of 0.8 µg/mL. All other compounds showed the good activity with a MIC value of 6.25-100 µg/mL. The compounds were further tested for mammalian cell toxicity using human lung cancer cell-line (A549) and were nontoxic. Some compounds exhibited inhibition activities against InhA.

Synthesis, characterization and antitubercular activities of novel pyrrolyl hydrazones and their Cu-complexes.

Novel pyrrolyl hydrazones and their copper complexes have been synthesized and characterized using analytical and spectral techniques to show the tetrahedral geometry for Cu(II) complexes. Biological activities of hydrazones have been assessed to understand the role of metal ion on their biological activity and the effect of pyrrolyl hydrazones. In vitro antitubercular activity against Mycobacterium tuberculosis of the metal complexes (13b and 13r) exhibited the highest antitubercular activity that are quite close to rifampicin (0.4 µg/mL), giving a MIC of 0.8 µg/mL. All other compounds showed good activity with the MIC values ranging from 1.6 to 100 µg/mL. A comparative study of inhibition values of the ligands and their complexes showed higher antimicrobial activity of the complexes than the ligands. Some compounds have a good activity against InhA and in particular, compounds 12r, 13b and 13r exhibited more than 60% binding with the enzyme even at 5 µM (exhibited good IC50 upto 2.4 µM). Most of the active molecules have a very less cytotoxicity against the human lung cancer cell-line A549. The docking and 3D-QSAR studies have been carried out to provide some insights into the mechanism of action for this class of compounds.

A click chemistry approach for the synthesis of mono and bis aryloxy linked coumarinyl triazoles as anti-tubercular agents.

A series of mono and bis-triazole coumarin hybrids 6a-u and 9a-f respectively have been synthesized using 4-(azidomethyl)-2H-chromen-2-ones 5a-i and aryl propargyl ethers 2a-c/8 employing Click chemistry modified protocol for Azide-Alkyne cycloadditions(CuAAC). Anti-tubercular screening showed moderate activity for mono aryloxy compounds 6a-u with MIC 50-100 µg/mL, whereas the bis compounds 9a-f were more effective with MICs between 0.2 and 12.5 µg/mL. Molecular modeling and 3D-QSAR measurements using CoMFA and Topomer CoMFA further supported the observed results. The bis compound 9b showed excellent activity with MIC value as low as 0.2 µg/mL.