Design, synthesis, molecular docking and pharmacological evaluation of some thiadiazole based nipecotic acid derivatives as a potential anticonvulsant and antidepressant agents.

In our continuous effort to develop novel antiepileptic drug, a new series of nipecotic acid derivatives having1,3,4-thiadiazole nucleus were designed and synthesized. This study aims to improve the lipophilicity of nipecotic acid by attaching some lipophilic anchors like thiadiazole and substituted aryl acid derivatives. In our previous study, we noticed that the N-substituted oxadiazole derivative of nipecotic acid exhibited significant antiepileptic activity in the rodent model. The synthesized compounds were characterized by FT-IR, 1H-NMR, 13C-NMR, Mass, and elemental analysis. The anticonvulsant activity was evaluated by using the maximal electroshock-induced seizure model in rats (MES) and the subcutaneous pentylenetetrazol (scPTZ) test in mice. None of the compounds were found to be active in the MES model whereas compounds (TN2, TN9, TN12, TN13, and TN15) produced significant protection against the scPTZ-induced seizures model. The compounds showing antiepileptic activity were additionally evaluated for antidepressant activity by using the forced swim test, 5-hydroxytryptophan (5-HTP)-induced head twitch test, and learned helplessness test. All the molecules that showed anticonvulsant activity (TN2, TN9, TN12, TN13, and TN15), also exerted significant antidepressant effects in the animal models. The selected compounds were subjected to different toxicity studies. Compounds were found to have no neurotoxicity in the rota-rod test and devoid of hepatic and renal toxicity in 30 days repeated oral toxicity test. Further, a homology model was developed to perform the in-silico molecular docking and dynamics studies which revealed the similar binding of compound TN9 within the active binding pocket and were found to be the most potent anti-epileptic agent. The market expectation for newly developed antiepileptic thiadiazole-based nipecotic acid derivatives is significant, driven by their potential to offer improved therapeutic outcomes and reduced side effects, addressing a critical need in epilepsy treatment. These innovative compounds hold promise for meeting the demand for more effective and safer antiepileptic medications. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03897-1.

Identification of natural lead molecules as potential Trypanosoma cruzi cruzipain inhibitors and decoding the interaction mechanism for the treatment of Chagas disease: a computational biology analysis.

Chagas disease has grown into a serious public health threat, with a high morbidity rate, major social impact, and global neglect. Therapeutic adhesion, unwanted side-effects, and resistance make its present therapy ineffective. Discovery of more effective drugs is hence needed. Using natural compounds conjointly with computational methods helps better to find promising compounds, speeding up drug discovery process and reducing its cost. In the present study, a docking protocol against cruzipain (PDB: 3l06), an important druggable target, was applied to a library of 50 sorted natural compounds. Compounds were further analysed for binding mode and interactions with cruzipain active site, conformational alignment studies and in-silico pharmacokinetic studies so as to predict their plausible anti-cruzipain mechanism. The results provided computational insights into the molecular interaction of naturals against T. cruzi cruzipain. Study also lead to identification of Hinokiflavone; BA = -10.2 kcal mol-1 as reasonably promising potential natural cruzipain inhibitor.

Selective inhibition of peptidyl-arginine deiminase (PAD): can it control multiple inflammatory disorders as a promising therapeutic strategy?

Peptidyl arginine deiminases (PADs) are a family of post-translational modification enzymes that irreversibly citrullinate (deiminate) arginine residues of protein and convert them to a non-classical amino acid citrulline in the presence of calcium ions. It has five isotypes, such as PAD1, PAD2, PAD3, PAD4, and PAD6, found in mammalian species. It has been suggested that increased PAD expression in various tissues contributes to the development of multiple inflammatory diseases, including rheumatoid arthritis (RA), cancer, diabetes, and neurological disorders. Elevation of PAD enzyme expression depends on several factors like rising intracellular Ca2+ levels, oxidative stress, and proinflammatory cytokines. PAD inhibitors originating from natural or synthetic sources can be used as a novel therapeutic approach concerning inflammatory disorders. Here, we review the pathological role of PAD in several inflammatory disorders, factors that trigger PAD expression, epigenetic role and finally, decipher the therapeutic approach of PAD inhibitors in multiple inflammatory disorders.

Design, synthesis, evaluation and molecular modelling studies of some novel 5,6-diphenyl-1,2,4-triazin-3(2H)-ones bearing five-member heterocyclic moieties as potential COX-2 inhibitors: A hybrid pharmacophore approach.

A series of novel hybrids comprising of 1,3,4-oxadiazole/thiadiazole and 1,2,4-triazole tethered to 5,6-diphenyl-1,2,4-triazin-3(2H)-one were designed, synthesised and evaluated as COX-2 inhibitors for the treatment of inflammation. The synthesised hybrids were characterised using FT-IR, 1H NMR, 13C NMR, elemental (C,H,N) analyses and assessed for their anti-inflammatory potential by in vitro albumin denaturation assay. Compounds exhibiting activity comparable to indomethacin and celecoxib were further evaluated for in vivo anti-inflammatory activity. Oral administration of promising compounds 3c-3e and 4c-4e did not evoke significant gastric, hepatic and renal toxicity in rats. These potential compounds exhibited reduced malondialdehyde (MDA) content on the gastric mucosa suggesting their protective effects by inhibition of lipid peroxidation. Based on the outcome of in vitro COX assay, compounds 3c-3e and 4c-4e (IC50 0.60-1.11µM) elicited an interesting profile as competitive selective COX-2 inhibitors. Further, selected compounds 3e and 4c were found devoid of cardiotoxicity post evaluation on myocardial infarcted rats. The in silico binding mode of the potential compounds into the COX-2 active site through docking and molecular dynamics exemplified their consensual interaction and subsequent COX-2 inhibition with significant implications for structure-based drug design.

Leishmania donovani Aurora kinase: A promising therapeutic target against visceral leishmaniasis.

BACKGROUND: Aurora kinases are key mitotic kinases executing multiple aspects of eukaryotic cell-division. The apicomplexan homologs being essential for survival, suggest that the Leishmania homolog, annotated LdAIRK, may be equally important. METHODS: Bioinformatics, stage-specific immunofluorescence microscopy, immunoblotting, RT-PCR, molecular docking, in-vitro kinase assay, anti-leishmanial activity assays, flow cytometry, fluorescence microscopy. RESULTS: Ldairk expression is seen to vary as the cell-cycle progresses from G1 through S and finally G2M and cytokinesis. Kinetic studies demonstrate their enzymatic activity exhibiting a Km and Vmax of 6.12µM and 82.9pmoles·min(-1)mg(-1) respectively against ATP using recombinant Leishmania donovani H3, its physiological substrate. Due to the failure of LdAIRK-/+ knock-out parasites to survive, we adopted a chemical knock-down approach. Based on the conservation of key active site residues, three mammalian Aurora kinase inhibitors were investigated to evaluate their potential as inhibitors of LdAIRK activity. Interestingly, the cell-cycle progressed unhindered, despite treatment with GSK-1070916 or Barasertib, inhibitors with greater potencies for the ATP-binding pocket compared to Hesperadin, which at nanomolar concentrations, severely compromised viability at IC50s 105.9 and 36.4nM for promastigotes and amastigotes, respectively. Cell-cycle and morphological studies implicated their role in both mitosis and cytokinesis. CONCLUSION: We identified an Aurora kinase homolog in L. donovani implicated in cell-cycle progression, whose inhibition led to aberrant changes in cell-cycle progression and reduced viability. GENERAL SIGNIFICANCE: Human homologs being actively pursued drug targets and the observations with LdAIRK in both promastigotes and amastigotes suggest their potential as therapeutic-targets. Importantly, our results encourage the exploration of other proteins identified herein as potential novel drug targets.

Synthesis, characterization, evaluation and molecular dynamics studies of 5, 6-diphenyl-1,2,4-triazin-3(2H)-one derivatives bearing 5-substituted 1,3,4-oxadiazole as potential anti-inflammatory and analgesic agents.

A series of triazin-3(2H)-one derivatives bearing 1,3,4-oxadiazole (4a-4o) were synthesized, characterized and evaluated for anti-inflammatory and analgesic activities. Preliminary in vitro anti-inflammatory activity was assessed using an albumin denaturation assay. The promising compounds were further evaluated in acute, sub-chronic and chronic animal models of inflammation. Derivatives 4d, 4e, 4g, 4j and 4l exhibited significant anti-inflammatory activity with reduced ulcerogenic, hepatotoxic and renotoxic liabilities compared to standard indomethacin. These potential derivatives were also evaluated for in vivo analgesic activity using a writhing model and the formalin-induced paw licking response in mice. Compounds 4d, 4e and 4g exhibited comparable analgesic activity, whereas 4j and 4l yielded moderate effects. The specificity of compounds 4d, 4e, 4g, 4j, and 4l to inhibit (cyclooxygenase-1) COX-1 and (cyclooxygenase-2) COX-2 isozymes and their kinetics were also determined via an in vitro COX inhibition assay. In silico docking studies were performed using a molecular dynamics simulation of the most active compound 4d (COX-2 IC50: 3.07 µM) at the COX-2 active site. The outcome of this exercise helped to verify the consensual interaction of these compounds with the enzyme.

Facile Synthesis, Characterization, and In Vitro Antimicrobial Screening of a New Series of 2,4,6-Trisubstituted-s-triazine Based Compounds.

A series of new 2,4,6-trisubstituted-s-triazine was synthesized, assessed for antimicrobial activity, and characterized by FTIR, (1)HNMR, (13)CNMR, and elemental analysis. The tested compounds, 4d, 4g, 4h, 4k, and 4n, have shown considerable in vitro antibacterial efficacy with reference to the standard drug ciprofloxacin (MIC 3.125 µgmL(-1) against B. subtilis, E. coli, and K. pneumoniae). It was observed that compounds 4d and 4h displayed equipotent antibacterial efficacy against B. subtilis (MIC 3.125 µgmL(-1)) and S. aureus (MIC 6.25 µgmL(-1)). The studies demonstrated that the para-fluorophenylpiperazine substituted s-triazine (4n) was potent and exhibited broad spectrum antibacterial activity against S. epidermidis, K. pneumoniae, and P. aeruginosa with MIC of 6.25 µgmL(-1) and for E. coli, it showed an MIC of 3.125 µgmL(-1) equipotent with reference to the standard drug. Among all the compounds under investigation, compound 4g also demonstrated significant antifungal activity (3.125 µgmL(-1)) against C. albicans.

Design, synthesis and pharmacological evaluation of N3 aryl/ heteroaryl substituted 2-((benzyloxy and phenylthio) methyl) 6,7- dimethoxyquinazolin-4(3H)-ones as potential anticonvulsant agents.

Novel N3 aryl/heteroaryl substituted 2-((benzyloxy and phenylthio) methyl) 6,7-dimethoxyquinazolin-4(3H)- ones (8a-8l) were synthesized and evaluated for their anticonvulsant activity using various models of epilepsy, such as maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and intracerebroventricular AMPA (α-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid)-induced seizures in mice. The rotarod test has been used to determine the acute neurotoxicity. Further, the serum enzymatic activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were assessed along with histopathological examination of liver. Among all the derivatives, compound 8f displayed significant activity profile based on the overall magnitude of activity and minimum neurotoxicity.

Synthesis, characterization, biological evaluation and docking of coumarin coupled thiazolidinedione derivatives and its bioisosteres as PPARγ agonists.

Thiazolidinedione (TZD) derivatives are the novel class of oral antidiabetic drugs which are selective agonist for the nuclear PPAR γ that enhances the transcription of several insulin responsive genes but TZDs are known to cause weight gain, hepatotoxicity and fluid retention. So a new series of coumarin coupled thiazolidinedione derivatives and its bioisosters (oxazolidinedione and imidazolidinedione) were synthesized by Knoevenagel condensation of 4-((7-hydroxy-2-oxo-2H-chromen-4-yl) methoxy) benzaldehyde with 2,4 thiazolidinedione and its bioisosteres. The structures of these compounds were established by means of FT IR, 1H-NMR, elemental analysis and mass spectroscopy. All the compounds were screened for antidiabetic activity in streptozotocin induced diabetic wistar male rats. Most of the compounds revealed significant antidiabetic activity when compared with the standard drug rosiglitazone. Compounds 5 & 6 containing oxazolidinedione ring system were found to be more active than compounds having thiazolidinedione and imidazolidinedione nucleus. Molecular docking was performed on 2 PRG protein by using the software Glide (Schrödinger, LLC, USA). The QikProp program was used to obtain the pharmacokinetic properties of analogues.

Nanocrystal technology in the delivery of poorly soluble drugs: an overview.

Extensive attempts to overcome problems related to solubility of drugs for maximizing bioavailability at targeted sites in the body have been made. The issue of drug solubility appears to attract the continued interest of pharmaceutical manufacturers. In this context, nanocrystallization has emerged as an important tool. In the present review, the authors discuss the advantages of nanocrystallized drugs and examine the products available in the market as well as drugs in the pipeline using nanocrystal-based formulations, which are being developed by pharmaceutical companies for drug delivery.

Pharmacophoric modeling and atom-based 3D-QSAR of novel 1-aryl-3-(1-acylpiperidin-4-yl) urea as human soluble epoxide hydrolase inhibitors (sEHIs).

Soluble Epoxide Hydrolase (sEH) is an important and promising new pharmacologic target for the treatment of acute systemic inflammation. Inhibition of sEH by a highly selective and potent sEH inhibitor (sEHI) elevates the epoxyeicosatrienoic acids (EETs) level in vivo leading to decreased inflammation. To explore the necessary structural requirement of 1, 3-disubstituted ureas as sEH inhibitors for anti-inflammatory activity, the molecular modeling studies have been pursued. A ligand-based pharmacophoric model and atom-based 3D-QSAR have been generated by Phase. Binding interaction as determined by the docking study revealed that these inhibitors interact at active site (ASP 335 & TYR 383) of sEH enzyme. The pharmacophore model was further used as a 3D query for virtual screening to retrieve potential inhibitors.

Antimalarial drug development: past to present scenario.

Malaria is a global health problem that needs attention of drug discovery scientists to investigate novel compounds with high drug efficacy, safety and low cost to counter the malaria parasites that are resistant to existing drug molecules. This is an overview of past to present status of antimalarial drugs including newly researched candidates and also the alternative approaches for the complete control of malaria.