Design, Synthesis and Biological Activity Evaluation of S-Substituted 1H-5-Mercapto-1,2,4-Triazole Derivatives as Antiproliferative Agents in Colorectal Cancer

Design, synthesis, computational molecular docking studies of novel heterocyclics bearing 1,2,4-triazole, 1,3,4-oxadiazole conjugates as potent antibacterial and antitubercular agents

Herein, we report the synthesis, and characterization of a new series of 1,3,4-oxadiazole and 1,2,4-triazole derivatives based on azaindole acetamides and assigned as potential antibacterial and antitubercular substances. The structures of these compounds were established by 1H NMR, 13C NMR, and HRMS spectral analysis. In preliminary antibacterial studies, analogues 6b, 6d, and 6e were found to be most effective against S. aureus with MIC of 12.5, 6.25, and 12.5 μg/mL, whereas 8d displayed excellent activity against S. aureus, B. subtilis, E. coli bacterial strains with zones of inhibition 12.5, 25, and 12.5 μg/mL respectively. Particularly, the prepared scaffolds 8c, 8d, and 8e showed remarkable antifungal activity with MIC value 12.5, 12.5, and 6.25 μg/mL against A. flavus and 6d, 6c producing an increase in the activity against C. Albicans with zones of inhibition 12.5 and 12.5 μg/mL respectively. Also, through the antitubercular studies, we found that compounds 6e and 8b have a strong activity with M. tuberculosis H37Rv with MICs 3.26, and 6.48 μg/mL, respectively. The protein stability, fluctuations of APO-Protein, and protein-ligand complexes were investigated through Molecular Dynamics (MD) simulations studies using Desmond Maestro 11.3, and potential lead molecules were identified. Our findings were further confirmed using molecular docking, revealing that azaindole based ligand 6e, 6f, and 8a has strong hydrophobic Tyr179, Trp183, Ile177, Ile445, and H-bondings interactions Arg151 and Arg454 through molecular dynamics simulation studies, making it potential biological compound. These compounds were further evaluated for their ADMET and physicochemical properties by using SwissADME.Communicated by Ramaswamy H. Sarma.

Solvent- and functional-group-assisted tautomerism of 3-alkyl substituted 5-(2-pyridyl)-1,2,4-triazoles in DMSO-water

The tautomerism of a series of 5-alkyl substituted 3-(2-pyridyl)-1,2,4-triazoles in DMSO-d6-containing water has been investigated by 1H, 13C and 15N NMR spectroscopy. The populations of the three possible regioisomers in the tautomeric equilibrium (A [3-alkyl-5-(2-pyridyl)-1H], B [5-alkyl-3-(2-pyridyl)-1H] and C [5-alkyl-3-(2-pyridyl)-4H]) were determined. Isomers A (17-40%) and B (54-79%) are the major components and their ratio is insensitive to the substitution pattern, except for the unsubstituted and the methoxymethyl substituted derivatives. The isomer C (3-5%) has been fully characterised for the first time by NMR spectroscopy. Activation energies of tautomerisation (14.74-16.78 kcal mol-1) were determined by EXSY experiments, which also supported the involvement of water in the tautomerisation. Substituent effects on the 15N chemical shifts are relatively small. The DFT study of the tautomerism in DMSO-water showed that both A/B and B/C interconversions are assisted by the pyridine substituent and catalysed by solvent molecules. The NH-A/NH-B tautomerisation takes place via a relayed quadruple proton transfer mediated by three water molecules in the hydrogen-bonded cyclic substructure of a triazole·4H2O complex. The equilibrium B ⇄ C involves three steps: NH-B transfer to the pyridyl nitrogen mediated by a water molecule in a 1 : 1 cyclic complex, rotamerisation to bring the pyridinium NH close to N4 of the triazole catalysed by complexation to a DMSO molecule and transfer of the NH from the pyridinium donor to the N4 acceptor via a 1 : 1 complex with a bridging water molecule. This mechanism of 1,3-prototropic shift in triazoles is unprecedented in the literature.

Antiviral Effect of Polyphenolic Substances in Geranium wilfordii Maxim against HSV-2 Infection Using in vitro and in silico Approaches

Background

Herpes simplex virus type 2 (HSV-2) infestation was the most widespread STD (sexually transmitted diseases) among humans and was the leading cause of infectious recurrent genital herpes. Existing therapies against HSV-2 did incompletely restrain the comeback of activated HSV-2 infestation. Geranium wilfordii Maxim had long been used as traditional Chinese medicine for treating the diseases owing to its anti-inflammatory and antiviral effects. Herein, the study was designed to investigate the antiviral activity of G.wilfordii and its potential effect in regulating the host's immune response.

Methods

To identify the stage of infection at which the compounds inhibited HSV-2, we performed virucidal, therapeutic, and prophylactic assays. The antiviral efficacy was evaluated by the analysis of viral components HSV-2 gD and VP16. The antiviral activities of these compounds were also evaluated by phenotypic analysis, such as cell proliferation and apoptosis. Molecular docking studies on candidate compounds were done to indicate binding interactions between the compounds and adopted compound targets.

Results

Quercetin, corilagin, and geraniin inhibited the replication of HSV-2, with geraniin showing greater TI. The obtained IC₅₀ value of quercetin was 204.7 μM and TI (IC₅₀/EC₅₀) was 5.1, whereas the obtained IC₅₀ value of corilagin was 118.0 μg/ml and TI was 4.05. Geraniin exhibited prominent antiviral activity with an IC₅₀ of 212.4 μM and an EC₅₀ of 18.37 μM, resulting in a therapeutic index (TI) of 11.56. Geraniin showed important in vitro virucidal activity through blocking viral attachment. Compared with the virus group, the apoptosis rates in quercetin-, corilagin-, and geraniin-treated groups were significantly decreased (p < 0.001).The expressions at the transcription genes of virus own replication key factors (including HSV-2 gD and VP16) and cytokines (including TBK1) of infected cells treated with quercetin, corilagin, and geraniin were inhibited. The in silico approaches demonstrated a high number of potential strong intermolecular interactions as hydrogen bonds between geraniin, corilagin, and the activity site of HSV-2 gD. Molecular docking studies demonstrated the effects of corilagin by targeting TBK1.

Conclusions

Together, these results highlighted the importance of G.wilfordii treatment in HSV-2 infection and underscored its therapeutic potential. However, additional in vitro and in vivo research was required to validate our findings.

Triazoles and Their Derivatives: Chemistry, Synthesis, and Therapeutic Applications

Among the nitrogen-containing heterocyclic compounds, triazoles emerge with superior pharmacological applications. Structurally, there are two types of five-membered triazoles: 1,2,3-triazole and 1,2,4-triazole. Due to the structural characteristics, both 1,2,3- and 1,2,4-triazoles are able to accommodate a broad range of substituents (electrophiles and nucleophiles) around the core structures and pave the way for the construction of diverse novel bioactive molecules. Both the triazoles and their derivatives have significant biological properties including antimicrobial, antiviral, antitubercular, anticancer, anticonvulsant, analgesic, antioxidant, anti-inflammatory, and antidepressant activities. These are also important in organocatalysis, agrochemicals, and materials science. Thus, they have a broad range of therapeutic applications with ever-widening future scope across scientific disciplines. However, adverse events such as hepatotoxicity and hormonal problems lead to a careful revision of the azole family to obtain higher efficacy with minimum side effects. This review focuses on the structural features, synthesis, and notable therapeutic applications of triazoles and related compounds.

Spirostane saponins with a rearranged A/B ring system isolated from the rhizomes of Ophiopogon japonicus

In this study, the popular food and medicinal herb Ophiopogon japonicus was investigated alongside a 70% ethanol extract of its rhizomes, revealing twenty-three steroidal glycosides with four undescribed steroidal saponins, named ophiopogonols A-D. Among them, ophiopogonols A-B are two unusual spirostanols with a rearranged A/B ring system (5/7/6/5/5/6 ring system) that have not previously been identified in plants. The chemical structures of all isolated steroidal glycosides were elucidated by comprehensive analysis through chemical methods, HRESIMS, and NMR spectroscopy. Further, putative biosynthetic pathways for ophiopogonols A-B were proposed. In addition, based on traditional applications of O. japonicus, cytotoxic effects of the isolates were evaluated using human large cell lung carcinoma cells (NCI-H460 cells). Sprengerinin C displayed a remarkable cytotoxic effect with IC₅₀ values of 2.1 ± 0.8 μM by inducing apoptosis and G2/M phase cycle arrest in the NCI-H460 cell line.

New Investigations with Lupane Type A-Ring Azepane Triterpenoids for Antimycobacterial Drug Candidate Design

Twenty lupane type A-ring azepano-triterpenoids were synthesized from betulin and its related derivatives and their antitubercular activity against Mycobacterium tuberculosis, mono-resistant MTB strains, and nontuberculous strains Mycobacterium abscessus and Mycobacterium avium were investigated in the framework of AToMIc (Anti-mycobacterial Target or Mechanism Identification Contract) realized by the Division of Microbiology and Infectious Diseases, NIAID, National Institute of Health. Of all the tested triterpenoids, 17 compounds showed antitubercular activity and 6 compounds were highly active on the H37Rv wild strain (with MIC 0.5 µM for compound 7), out of which 4 derivatives also emerged as highly active compounds on the three mono-resistant MTB strains. Molecular docking corroborated with a machine learning drug-drug similarity algorithm revealed that azepano-triterpenoids have a rifampicin-like antitubercular activity, with compound 7 scoring the highest as a potential M. tuberculosis RNAP potential inhibitor. FIC testing demonstrated an additive effect of compound 7 when combined with rifampin, isoniazid and ethambutol. Most compounds were highly active against M. avium with compound 14 recording the same MIC value as the control rifampicin (0.0625 µM). The antitubercular ex vivo effectiveness of the tested compounds on THP-1 infected macrophages is correlated with their increased cell permeability. The tested triterpenoids also exhibit low cytotoxicity and do not induce antibacterial resistance in MTB strains.

3-Pyridinylidene Derivatives of Chemically Modified Lupane and Ursane Triterpenes as Promising Anticancer Agents by Targeting Apoptosis

Cancer persists as a global challenge due to the extent to which conventional anticancer therapies pose high risks counterbalanced with their therapeutic benefit. Naturally occurring substances stand as an important safer alternative source for anticancer drug development. In the current study, a series of modified lupane and ursane derivatives was subjected to in vitro screening on the NCI-60 cancer cell line panel. Compounds 6 and 7 have been identified as highly active with GI₅₀ values ranging from 0.03 µM to 5.9 µM (compound 6) and 0.18–1.53 µM (compound 7). Thus, these two compounds were further assessed in detail in order to identify a possible antiproliferative mechanism of action. DAPI (4′,6-diamidino-2-phenylindole) staining revealed that both compounds induced nuclei condensation and overall cell morphological changes consistent with apoptotic cell death. rtPCR analysis showed that both compounds induced upregulation of proapoptotic Bak and Bad genes while downregulating Bcl-XL and Bcl-2 antiapoptotic genes. Molecular docking analysis revealed that both compounds exhibited high scores for Bcl-XL inhibition, while compound 7 showed higher in silico Bcl-XL inhibition potential as compared to the native inhibitor ATB-737, suggesting that compounds may induce apoptotic cell death through targeted antiapoptotic protein inhibition, as well.

Recent developments in mitogen activated protein kinase inhibitors as potential anticancer agents

The mitogen activated protein kinase (MAPK) belongs to group of kinase that links the extracellular stimuli to intracellular response. The MAPK signalling pathway (RAS-RAF-MEK-ERK) involved in different pathological conditions like cancer, caused due to genetic or any other factor such as physical or environmental. Many studies have been conducted on the pathological view of MAPK cascade and its associated element like RAS, RAF, MEK, ERK or its isoforms, and still the research is going on particularly with respect to its activation, regulation and inhibition. The MAPK signalling pathway has become the area of research to identify new target for the management of cancer. A number of heterocyclics are key to fight with the cancer associated with these enzymes thus give some hope in the management of cancer by inhibiting MAPK cascade. In the present article, we have focussed on MAPK signalling pathway and role of different heterocyclic scaffolds bearing nitrogen, sulphur and oxygen and about their potential to block MAPK signalling pathway. The heterocyclics are gaining importance due to high potency and selectivity with less off-target effects against different targets involved in the MAPK signalling pathway. We have tried to cover recent advancements in the MAPK signalling pathway inhibitors with an aim to get better understanding of the mechanism of action of the compounds. Several compounds in the preclinical and clinical studies have been thoroughly dealt with. In addition to the synthetic compounds, a significant number of natural products containing heterocyclic moieties as MAPK signalling pathway inhibitors have been put together. The structure activity relationship along with docking studies have been discussed to apprehend the mechanistic studies of various compounds that will ultimately help to design and develop more MAPK signalling pathway inhibitors.

Design, Synthesis, Molecular Modeling, Anticancer Studies, and Density Functional Theory Calculations of 4-(1,2,4-Triazol-3-ylsulfanylmethyl)-1,2,3-triazole Derivatives

New conjugates of substituted 1,2,3-triazoles linked to 1,2,4-triazoles were synthesized starting from the appropriate S-propargylated 1,2,4-triazoles 7 and 8. Ligation of 1,2,4-triazoles to the 1,2,3-triazole core was performed through Cu(I)-catalyzed cycloaddition of 1,2,4-triazole-based alkyne side chain 7 and/or 8 with several un/functionalized alkyl- and/or aryl-substituted azides 9-15 to afford the desired 1,4-disubstituted 1,2,3-triazoles 16-27, using both classical and microwave methods. After their spectroscopic characterization (infrared, 1H, 13C nuclear magnetic resonance, and elemental analyses), an anticancer screening was carried out against some cancer cell lines including human colon carcinoma (Caco-2 and HCT116), human cervical carcinoma (HeLa), and human breast adenocarcinoma (MCF-7). The outcomes of this exploration revealed that compounds 17, 22, and 25 had a significant anticancer activity against MCF-7 and Caco-2 cancer cell lines with IC50 values of 0.31 and 4.98 μM, respectively, in relation to the standard reference drug, doxorubicin. Enzyme-docking examination was executed onto cyclin-dependent kinase 2; a promising aim for cancer medication. Synthesized compounds acquiring highest potency showcased superior interactions with the active site residue of the target protein and exhibited minimum binding energy. Finally, the density functional theory (DFT) calculations were carried out to confirm the outcomes of the molecular docking and the experimental findings. The chemical reactivity descriptors such as softness (δ), global hardness (η), electronegativity (χ), and electrophilicity were calculated from the levels of the predicted frontier molecular orbitals and their energy gap. The DFT results and the molecular docking calculation results explained the activity of the most expectedly active compounds 17, 22, and 25.

Unravelling the anticancer potency of 1,2,4-triazole-N-arylamide hybrids through inhibition of STAT3: synthesis and in silico mechanistic studies

The discovery of potent STAT3 inhibitors has gained noteworthy impetus in the last decade. In line with this trend, considering the proven biological importance of 1,2,4-triazoles, herein, we are reporting the design, synthesis, pharmacokinetic profiles, and in vitro anticancer activity of novel C3-linked 1,2,4-triazole-N-arylamide hybrids and their in silico proposed mechanism of action via inhibition of STAT3. The 1,2,4-triazole scaffold was selected as a privilege ring system that is embedded in core structures of a variety of anticancer drugs which are either in clinical use or still under clinical trials. The designed 1,2,4-triazole derivatives were synthesized by linking the triazole-thione moiety through amide hydrophilic linkers with diverse lipophilic fragments. In silico study to predict cytotoxicity of the new hybrids against different kinds of human cancer cell lines as well as the non-tumor cells was conducted. The multidrug-resistant human breast adenocarcinoma cells (MDA-MB-231) was found most susceptible to the cytotoxic effect of synthesized compounds and hence were selected to evaluate the in vitro anticancer activity. Four of the designed derivatives showed promising cytotoxicity effects against selected cancer cells, among which compound 12 showed the highest potency (IC₅₀ = 3.61 µM), followed by 21 which displayed IC₅₀ value of 3.93 µM. Also, compounds 14 and 23 revealed equipotent activity with the reference cytotoxic agent doxorubicin. To reinforce these observations, the obtained data of in vitro cytotoxicity have been validated in terms of ligand-protein interaction and new compounds were analyzed for ADMET properties to evaluate their potential to build up as good drug candidates. This study led us to identify two novel C3-linked 1,2,4-triazole-N-arylamide hybrids of interesting antiproliferative potentials as probable lead inhibitors of STAT3 with promising pharmacokinetic profiles.

Molecular docking studies, biological evaluation and synthesis of novel 3-mercapto-1,2,4-triazole derivatives

Synthesis of bioactive heterocyclic compounds having effective biological activity is an essential research area for wide-ranging applications. In this study, a conventional methodology has been developed for the synthesis of a series of new 3-mercapto-1,2,4-triazole derivatives 4a-f. The purity and structure of the synthesized molecules were confirmed by ¹H NMR, ¹³C NMR and elemental analysis. In addition, the prepared compounds were screened for their anti-proliferative activity against three human cancer cell lines including A549 (lung cancer), MCF7 (breast cancer) and SKOV3 (ovarian cancer) using MTT reduction assay. All the tested compounds demonstrated remarkable cytotoxic activity with IC₅₀ values ranging from 3.02 to 15.37 µM. The heterocyclic compound bearing 3,4,5-trimethoxy moiety was found to be the most effective among the series displaying an IC₅₀ of 3.02 µM specifically against the ovarian carcinoma cancer cell line (SKOV3). Moreover, Annexin V-FITC/propidium iodide staining assay indicated that this compound can induce apoptosis in SKOV3 cells. Furthermore, cell cycle assay showed a significant cell cycle arrest at the G2/M phase in a dose-dependent manner for this compound. The molecular docking results was showed binding modes of potent compound 4d perfectly corroborated the suggestion of binding to the colchicine site. The entire results conclude that 3-mercapto-1,2,4-triazole derivatives can be synthesized by a green method for biological and pharmacological applications. New analogs of 3-mercapto-1,2,4-triazole potential derivatives for anti-proliferative activity were synthesized. Cytotoxic activity of all synthesized compounds was evaluated against tree human cancer cell lines: lung (A549), breast (MCF7) and ovarian (SKOV3).