Design, synthesis, antimicrobial evaluation and docking studies of urea-triazole-amide hybrids

Novel benzimidazole hybrids: design, synthesis, mechanistic studies, antifungal potential and molecular dynamics

In this study, two series of benzimidazole hybrids were developed and designed using different strategies. The target compounds were designed through straight chemistry pathways and were screened as possible antimicrobial agents. Twenty new compounds were synthesized, among which compounds 11 and 12 displayed excellent activity against Candida albicans and Cryptococcus neoformans with growth inhibition percentage ranging from 86.42% to 100%. For gaining better insights into the mechanistic ability of the active candidates 11 and 12, their inhibitory activity against lanosterol 14α-demethylase was studied. Results showed IC50 values of 5.6 and 7.1 μM for 11 and 12, respectively, which were comparable to the reference value of fluconazole (2.3 μM), indicating low drug interaction possibilities. Notably, compound 11 displayed excellent inhibition of biofilm metabolic activity. In addition, their synergistic activity against C. neoformans displayed a 2-fold increase compared with fluconazole. Furthermore, it exhibited sustained antifungal activity with time clearance of over 24 h, which was better than the time clearance of fluconazole (6 h). Moreover, compounds 11 and 12 displayed considerable safety profiles, with no cytotoxicity reported against human embryonic kidney cells or hemolysis of red blood cells. Molecular dynamics simulation (MDS) experiments over 100 ns of compound 11 showed its ability to interact with the HEM binding site as the co-crystallized ligand (fluconazole). Finally, in silico ADMET studies predicted its significant oral bioavailability as antifungal candidates.

Current advancements and future perspectives of 1,2,3-triazoles to target lanosterol 14α-demethylase (CYP51), a cytochrome P450 enzyme: A computational approach

Antifungal resistance has become a significant challenge, necessitating the development of novel antifungal agents. Resistance often arises from prolonged and widespread use of existing treatments, leading to mutations in fungal enzymes that reduce drug efficacy. Amongst various scaffolds, 1,2,3-triazoles have emerged as antifungal agents due to their ability to bind effectively to fungal enzymes. This review examines the binding interactions of 1,2,3-triazoles with lanosterol 14α-demethylase (CYP51), an enzyme in Candida albicans (PDB IDs:5TZ1and5V5Z), highlighting their potential in fighting resistance. The CYP51 family is a captivating topic to investigate the structural and functional roles of P450 and makes for a key medical focus. It is one of crucial step in biosynthesis of sterol in eukaryotes. Antifungals mostly work on CYP51 and could also be used to treat protozoan diseases in the future. 1,2,3-Triazoles exert their antifungal effects by inhibiting the CYP51 enzyme, which is crucial for ergosterol synthesis in fungal cell membranes thereby leading to disruption of membrane integrity and ultimately leads to death of fungal cell. In silico studies like molecular docking and molecular dynamics (MD) simulations, reveal that these compounds establish strong interactions (e.g., π-π, π-alkyl, CH, hydrogen bonding, and Van der Waals interactions) with active site residues, stabilizing the ligand-enzyme complex. This review of virtual screening assays shows the adaptability of the 1,2,3-triazole scaffold and its widespread use in core antifungal compounds, making it a key pharmacophore for new lead development against resistant fungal species.

Pyrazoline Spiro-oxindole tethered 1,2,3-triazole hybrids: Design, synthesis, antimicrobial efficacy and molecular modelling studies

Inspired from the important applications of spirocyclic compounds in medicinal chemistry, a new series of pyrazoline Spiro-oxindole tethered 1,2,3-triazole hybrids was reported via Cu(I)-catalyzed click reaction from isatin-pyrazoline linked terminal alkynes with in situ derived benzyl azides. Antimicrobial evaluation data showed that all hybrids exhibited promising efficacy towards the tested microbial strains. Antimicrobial screening as well as docking studies suggested that hybrid 6a was found to be most potent towards Aspergillus niger (MIC = 0.0122 μmol/mL) and Escherichia coli (MIC = 0.0061 μmol/mL). Molecular docking studies of 6a within the binding pockets of antibacterial and antifungal targets revealed good interactions with the binding energies of - 144.544 kcal/mol and - 154.364 kcal/mol against 1KZN (E. coli) and 3D3Z (A. niger), respectively. Further, MD simulations were performed to study the stability of the complexes formed at 300 K. Based on the RMSD trajectories, it is evident that 3D3Z-6a complex exhibits minimal deviation, whereas the 1KZN-6a complex displayed little more deviation compared to the protein but, both are in acceptable range. Moreover, 3D3Z-6a and 1KZN-6a showed maximum number of hydrogen bonds at 50 ns and 70 ns, respectively, thereby complementing the stability of these complexes.

Synthesis, Characterization, Antimicrobial and In Silico Studies of Isatin Schiff Base Linked 1,2,3-Triazole Hybrids

A new series of isatin-Schiff base linked 1,2,3-triazole hybrids has been synthesized using CuAAC approach from (E)-3-(phenylimino)-1-(prop-2-yn-1-yl)indolin-2-one derivatives in high yield (73-91 %). These synthesized derivatives were characterized using FT-IR, 1H NMR, 13C NMR, 2D-NMR and HRMS spectral techniques. The in vitro antimicrobial activity assay demonstrated that most of the tested hybrids exhibited promising activity. Compound 5 j displayed significant antibacterial efficacy against P. aeruginosa and B. subtilis with MIC value of 0.0062 μmol/mL. While, 5 j also showed better antifungal potency against A. niger with MIC value of 0.0123 μmol/mL. The docking studies of most promising compounds were performed with the well-known antibacterial and antifungal targets i. e. 1KZ1, 5TZ1. Molecular modelling investigations demonstrated that hybrids 5 h and 5 l exhibited good interactions with 1KZN and 5TZ1, with binding energies of -9.6 and -11.0 kcal/mol, respectively. Further, molecular dynamics studies of the compounds showing promising binding interactions were also carried out to study the stability of complexes of these hybrids with both the targets.

New 3-Hydroxypyridine-4-one Analogues: Their Synthesis, Antimicrobial Evaluation, Molecular Docking, and In Silico ADME Prediction

INTRODUCTION

Drug resistance to existing antimicrobial drugs has become a serious threat to human health, which highlights the need to develop new antimicrobial agents.

METHODS

In this study, a new set of 3-hydroxypyridine-4-one derivatives (6a-j) was synthesized, and the antimicrobial effects of these derivatives were evaluated against a variety of microorganisms using the microdilution method. The antimicrobial evaluation indicated that compound 6c, with an electron-donating group -OCH3 at the meta position of the phenyl ring, was the most active compound against S. aureus and E. coli species with an MIC value of 32 μg/mL. Compound 6c was more potent than ampicillin as a reference drug.

RESULTS

The in vitro antifungal results showed that the studied derivatives had moderate effects (MIC = 128-512 μg/mL) against C. albicans and A. niger species. The molecular modeling studies revealed the possible mechanism and suitable interactions of these derivatives with the target protein.

CONCLUSION

The obtained biological results offer valuable insights into the design of more effective antimicrobial agents.

Recent advances in 1,2,3- and 1,2,4-triazole hybrids as antimicrobials and their SAR: A critical review

With the widespread use and sometimes even abuse of antibiotics, the problem of bacterial resistance to antibiotics has become very serious, and it is posing a great threat to global health. Therefore, development of new antibiotics is imperative. Triazoles are five-membered, nitrogen-containing aromatic heterocyclic scaffolds, with two isomeric forms, i.e. 1,2,3-triazole and 1,2,4-triazole. Triazole-containing compounds have a wide range of biological activities such as antibacterial, antifungal, anticancer, antioxidant, antitubercular, antimalarial, anti-HIV, anticonvulsant, anti-inflammatory, antiulcer, analgesic, and etc. The bioactivities and the diversity of triazole-containing drugs have attracted wide interest in these heterocycles. Various antibiotic triazole hybrids have been developed, and most of which have shown potent antimicrobial activities. In this review, we summarized the recent advances in triazole hybrids as potential antibacterial agents and their structure-activity relationships (SARs). The information gained through SAR studies will provide further insights into the development of new triazole antimicrobials.

Click synthesis, antimicrobial, DNA photocleavage and computational studies of oxindole-tethered 1H-1,2,3-triazoles

Aim: To obtain new hybrids derived from isatin and triazole. Materials & methods: A series of oxindole-1-H-1,2,3-triazole hybrids (4a-l) were synthesized from 3-sulfenylated N-propargylated oxindoles and organic azides employing Cu(I)-catalyzed azide-alkyne cycloaddition. These compounds were evaluated in vitro for antimicrobial activity by the standard serial dilution method and DNA photocleavage activity. Results: Antimicrobial assay revealed that compounds 4l and 4f exhibited promising efficacy against Candida albicans and Rhizopus oryzae, respectively, with a minimum inhibitory concentration value of 0.0008 μmol/mL. Compounds 4h and 4k completely degraded plasmid DNA. Further molecular docking of compounds with 1KZN (4j and 4k) and 5TZ1 (4h and 4l) revealed good binding interactions. Conclusion: Results of the current research can help in the development of new antimicrobial agents with high efficacy.

Development of new spiro[1,3]dithiine-4,11'-indeno[1,2-b]quinoxaline derivatives as S. aureus Sortase A inhibitors and radiosterilization with molecular modeling simulation

Multi-drug resistant microbes have become a severe threat to human health and arise a worldwide concern. A total of fifteen spiro-1,3-dithiinoindenoquinoxaline derivatives 2-7 were synthesized and evaluated for their biological activities against five standard and MDRB pathogens. The MIC and MBC/MFC for the most active derivatives were determined in vitro via broth microdilution assay. These derivatives showed significant activity against the tested strains with microbicidal behavior, with compound 4b as the most active compound (MIC range between 0.06 and 0.25 µg/mL for bacteria strains and MIC = 0.25 µg/mL for C. albicans). The most active spiro-1,3-dithiinoindenoquinoxaline derivatives were able to inhibit the activity of SrtA with IC₅₀ values ranging from 22.15 ± 0.4 µM to 37.12 ± 1.4 µM. In addition, the active spiro-1,3-dithiinoindenoquinoxaline attenuated the in vitro virulence-related phenotype of SrtA by weakening the adherence of S. aureus to fibrinogen and reducing the biofilm formation. Surprisingly, compound 4b revealed potent SrtA inhibitory activity with IC₅₀ = 22.15 µM, inhibiting the adhesion of S. aureus with 39.22 ± 0.15 % compared with untreated 9.43 ± 1.52 %, and showed a reduction in the biofilm biomass of S. aureus with 32.27 ± 0.52 %. We further investigated the effect of gamma radiation as a sterilization method on the microbial load and found that a dose of 5 kGy was sufficient to eradicate the microbial load. The quantum chemical studies exhibited that the tested derivatives have a small energy band gap (ΔE = -2.95 to -3.61 eV) and therefore exert potent bioactivity by interacting with receptors more stabilizing.

The crystal structure of 1-(4-bromophenyl)-3-(2-chlorobenzyl)urea, C14H12BrClN2O

C14H12BrClN2O, monoclinic, P21/c (no. 14), a = 13.4072(6) Å, b = 8.6103(5) Å, c = 12.3824(6) Å, β = 100.475(4), V = 1405.60(12) Å3, Z = 4, Rgt (F) = 0.0499, wRref (F 2) = 0.1215, T = 173 K.

Synthesis, spectroscopic characterization of novel phthalimides derivatives bearing a 1,2,3-triazole unit and examination as potential SARS-CoV-2 inhibitors via in silico studies

In the present study, novel phthalimide derivatives 8(a-f) and 9(a-f) bearing a 1,2,3-triazole subunit were synthesized via CuAAC reactions and characterized by 1H, 13C NMR, HR-MS, and FT-IR analyses. To support the fight against SARS-CoV-2, in silico molecular docking studies were carried out to examine their interactions with the proteins of SARS-CoV-2 (Mpro and PLpro) and the protein-protein interactions (PPI) between the ACE2-spike (S1) in comparison with various inhibitors reported to be active by in vitro experiments. The ligand-protein stabilities of compounds 8a-Mpro, 8b-PLpro, and 9a-'ACE2-S1' showing the best binding energy and predicted inhibition constant values (Ki) were examined by molecular dynamics simulation studies. Finally, in silico ADMET properties of the target compounds were investigated using the Swiss ADME and ProTox-II web tools. According to in silico results, all phthalimide analogs may block the PPI between S1 and ACE2. The compounds may also inhibit the progression of the Mpro, and PLpro proteins of SARS-CoV-2. Additionally, it has been estimated that the compounds are suitable for oral administration and exhibit low levels of toxicity.

Urea-thiazole/benzothiazole hybrids with a triazole linker: synthesis, antimicrobial potential, pharmacokinetic profile and in silico mechanistic studies

Some urea-thiazole/benzothiazole hybrids with a triazole linker were synthesized via Cu(I)-catalysed click reaction. After successfully analysed by various spectral techniques including FTIR, NMR and HRMS, antimicrobial screening of the synthesized hybrids along with their precursors was carried out against two Gram (+) bacteria (Staphylococcus aureus and Bacillus endophyticus), two Gram (-) bacteria (Escherichia coli and Pseudomonas fluorescens) and two fungi (Candida albicans and Rhizopus oryzae). All the synthesized compounds (4a-4l) displayed better biological response than the standard fluconazole against both of the tested fungi. Compounds 4h and 4j were found to be the most active compounds against R. oryzae and C. albicans, respectively. Molecular docking of hybrid 4j and its alkyne precursor 1b in the active site of C. albicans target sterol 14-α demethylase was also performed and was also supported by molecular dynamics studies. In silico ADME prediction of synthesized urea-thiazole/benzothiazole hybrids with a triazole linker and their alkyne precursors was also predicted.

1,2,3-Triazoles of 8-Hydroxyquinoline and HBT: Synthesis and Studies (DNA Binding, Antimicrobial, Molecular Docking, ADME, and DFT)

A new series of 1,2,3-triazole hybrids containing either 2- or 4-hydroxyphenyl benzothiazole (2- or 4-HBT) and naphthalen-1-ol or 8-hydroxyquinoline (8-HQ) was synthesized in high yields and fully characterized. In vitro DNA binding studies with herring fish sperm DNA (hs-DNA) showed that quinoline- and 2-HBT-linked 1,2,3-triazoles of shorter alkyl linkers such as 6a are better with a high binding affinity (3.90 × 105 L mol-1) with hs-DNA as compared to naphthol- and 4-HBT-linked 1,2,3-triazoles bound to longer alkyl linkers. Molecular docking of most active 1,2,3-triazoles 6a-f showed high binding energy of 6a (-8.7 kcal mol-1). Also, compound 6a displayed considerable antibacterial activity and superior antifungal activity with reference to ciprofloxacin and fluconazole, respectively. The docking results of the fungal enzyme lanosterol 14-α-demethylase showed high binding energy for 6a (-9.7 kcal mol-1) involving dominating H-bonds, electrostatic interaction, and hydrophobic interaction. The absorption, distribution, metabolism, and excretion (ADME) parameter, Molinspiration bioactivity score, and the PreADMET properties revealed that most of the synthesized 1,2,3-triazole molecules possess desirable physicochemical properties for drug-likeness and may be considered as orally active potential drugs. The electrophilicity index and chemical hardness properties were also studied by density functional theory (DFT) using the B3LYP/6-311G(d,p) level/basis set.

CDATA[Recent Advances in the Development of 1,2,3-Triazole-containing Derivatives as Potential Antifungal Agents and Inhibitors of Lanoster ol 14α-Demethylase

1,2,3-Triazole, a five-membered heterocyclic nucleus, is widely recognized as a key chromophore of great value in medicinal chemistry for delivering compounds possessing innumerable biological activities, including antimicrobial, antitubercular, antidiabetic, antiviral, antitumor, antioxidants, and anti-inflammatory activities. Mainly, in the past years, diverse conjugates carrying this biologically valuable core have been reported due to their attractive fungicidal potential and potent effects on various infective targets. Hence, hybridization of 1,2,3-triazole with other antimicrobial pharmacophores appears to be a judicious strategy to develop new effective anti-fungal candidates to combat the emergence of drug-sensitive and drug-resistant infectious diseases. Thus, the current review highlights the recent advances of this promising category of 1,2,3-triazole-containing hybrids incorporating diverse varieties of bioactive heterocycles such as conozole, coumarin, imidazole, benzimidazole, pyrazole, indole, oxindole, chromene, pyrane, quinazoline, chalcone, isoflavone, carbohydrates, and amides. It underlies their inhibition behavior against a wide array of infectious fungal species during 2015-2020.

Design, synthesis and mechanistic study of new 1,2,4-triazole derivatives as antimicrobial agents

Novel 5-amino-1,2,4-triazole derivatives and their cyclized 1,2,4-triazolo[1,5-a]pyrimidine analogues were designed, synthesized and evaluated for their antimicrobial activities. They were tested against five bacterial strains (Methicillin Resistant S. aureus (MRSA), E. coli, K. pneumoniae, A. baumannii and P. aeruginosa) using ciprofloxacin as a positive control and against two fungal strains (C. albicans and C. neoformans) using fluconazole and amphotericin B as positive controls. Compounds 9, 13a and 13b showed high to moderate antifungal activities against candida albicans (MIC values = 4-32 µg/ml), with considerable safety profiles; where no cytotoxicity against human embryonic kidney or red blood cells were detected at concentrations up to 32 µg/mL. Furthermore, compound 9 showed significant inhibitory activity against lansterol 14α-demethylase (IC₅₀ = 0.27 µM), compared to the reference drug fluconazole (IC₅₀ = 0.25 µM). Molecular docking of compound 9 into the active site of the cytochrome P450 enzyme revealed comparable binding modes and docking scores to those of fluconazole. Finally, in silico ADME studies prediction and drug-like properties of these compounds revealed favorable oral bioavailability results.

Synthesis of novel 2-methyl-3-furyl sulfide flavor derivatives as efficient preservatives

Foodborne microbial infestation seriously threatens food security, and the development of low-risk food preservatives is highly needed in food production. For discovering novel flavor molecules with antiseptic function, novel 2-methyl-3-furyl sulfide flavor derivatives were synthesized and evaluated. A wide range of 2-methyl-3-furyl sulfide derivatives were synthesized by reactions of 2-methyl-3-furyl disulfide with cyclic ethers, amides, ketones, and epoxides. All of these compounds have special aroma characteristics and low aroma thresholds. The antimicrobial activity of these compounds against test foodborne bacterial or fungal strains (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Salmonella paratyphi, Listeria monocytogenes, Vibrio parahemolyticus, Penicillium italicum, Aspergillus niger, Mucor racemosus, Rhizopus oryzae) was examined. It was found that fifteen compounds (3a, 3b, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 5a, 5b, 5f) have antimicrobial activity against different foodborne bacterial or fungal strains. Significantly, the antimicrobial activity of the flavor compounds (3b, 3d, 3e, 3i, 3j, 3l, 3m) is better than that of the control group (penicillin, amphotericin B and thiram), and they are promising preservatives for food production.

Foodborne microbial infestation seriously threatens food security, and the development of low-risk food preservatives is highly needed in food production.

Synthesis, antiproliferative activities, and DNA binding of coumarin-3-formamido derivatives

Ten coumarin-3-formamido derivatives, N-benzyl-coumarin-3-carboxamide (2), N-fluorobenzyl-coumarin-3-carboxamide (3-5), N-methoxybenzyl-coumarin-3-carboxamide (6-8), N-((1-methyl-1H-imidazol-5-yl)methyl)-coumarin-3-carboxamide (9), N-(thiophen-2-ylmethyl)-coumarin-3-carboxamide (10), and N-(furan-2-ylmethyl)-coumarin-3-carboxamide (11), were synthesized and characterized. Compound 5 crystallizes in a monoclinic system P2₁ /c space group with four chemical formulas in a unit cell; molecules of compound 5 are self-assembled into a two-dimensional supramolecular structure by intermolecular hydrogen bonds and C⋯C π stacking. The potential anticancer effects of these compounds on HeLa (cervical carcinoma), MCF-7 (breast), A549 (lung), HepG2 (liver), and human umbilical vein (HUVEC) cells were examined. Compared with compounds 1-8 and 10-11, compound 9 exhibits potent in vitro cytotoxicity against HeLa cells and lower cytotoxicity against normal cells. Therefore, further in-depth investigations of compound 9 were performed. Absorption titration experiments and fluorescence spectroscopy studies suggested that compound 9 binds to DNA through the intercalation mode.