Synthesis, antimalarial activity and molecular docking of hybrid 4-aminoquinoline-1,3,5-triazine derivatives

1,3,5-Triazine: Recent Development in Synthesis of its Analogs and Biological Profile

Triazine is an important pharmacophore in the field of research for the development of novel medications due to its presence in numerous powerful physiologically active compounds with significant medical potential, such as anti-tumor, anti-viral, anti-inflammatory, anti-microbial, anti- HIV, anti-leishmanial and others. The easy availability of triazine, high reactivity, simple synthesis of their analog, and their notable broad range of biological activities have garnered chemist interest in designing s-triazine-based drugs. The interest of medicinal chemists has been sparked by the structure-activity relationship of these biologically active entities, leading to the discovery of several promising lead molecules. Its importance for medicinal chemistry research is demonstrated by the remarkable progress made with triazine derivatives in treating a variety of disorders in a very short period. Authors have collated and reviewed the medicinal potential of s-triazine analogous to afford medicinal chemists with a thorough and target-oriented overview of triazine-derived compounds. We hope the present compilation will help people from the industry and research working in the medicinal chemistry area.

Hybrid PABA-glutamic acid conjugated 1,3,5-triazine derivatives: Design, synthesis, and antimalarial activity screening targeting Plasmodium falciparum dihydro folate reductase enzyme

Despite the successful reduction in the malaria health burden in recent years, it continues to remain a significant global health problem mainly because of the emerging resistance to first-line treatments. Also because of the disruption in malaria prevention services during the COVID-19 pandemic, there was an increase in malaria cases in 2021 compared to 2020. Hence, the present study outlined the in silico study, synthesis, and antimalarial evaluation of 1,3,5-triazine hybrids conjugated with PABA-glutamic acid. Docking study revealed higher binding energy compared to the originally bound ligand WR99210, predominant hydrogen bond interaction, and involvement of key amino acid residues, like Arg122, Ser120, and Arg59. Fourteen compounds were synthesized using traditional and microwave synthesis. The in vitro antimalarial evaluation against chloroquine-sensitive 3D7 and resistant Dd2 strain of Plasmodium falciparum showed a high to moderate activity range. Compounds C1 and B4 showed high efficacy against both strains and a further study revealed that compound C1 is non-cytotoxic against the HEK293 cell line with no acute oral toxicity. In vivo, study was performed for the most potent antimalarial compound C1 to optimize the research work and found to be effectively suppressing parasitemia of Plasmodium berghei strain in the Swiss albino mice model.

Roles of Virtual Screening and Molecular Dynamics Simulations in Discovering and Understanding Antimalarial Drugs

Malaria continues to be a global health threat, with approximately 247 million cases worldwide. Despite therapeutic interventions being available, patient compliance is a problem due to the length of treatment. Moreover, drug-resistant strains have emerged over the years, necessitating urgent identification of novel and more potent treatments. Given that traditional drug discovery often requires a great deal of time and resources, most drug discovery efforts now use computational methods. In silico techniques such as quantitative structure-activity relationship (QSAR), docking, and molecular dynamics (MD) can be used to study protein-ligand interactions and determine the potency and safety profile of a set of candidate compounds to help prioritize those tested using assays and animal models. This paper provides an overview of antimalarial drug discovery and the application of computational methods in identifying candidate inhibitors and elucidating their potential mechanisms of action. We conclude with the continued challenges and future perspectives in the field of antimalarial drug discovery.

Novel hybrids of quinoline with pyrazolylchalcones as potential antimalarial agents: Synthesis, biological evaluation, molecular docking and ADME prediction

A novel series of pyrazolyl chalcones containing quinoline scaffold, 5 a-v has been synthesized by Claisen Schimdt condensation of aromatic acetophenone with 1-(4-methylquinolin-2-yl)-3-aryl-1H-pyrazole-4-carbaldehyde in quantitative yield. The compounds were characterized using IR, NMR, MS and elemental analysis. An E-configuration about CC ethylenic bond was determined using ¹H NMR spectroscopy. These compounds exhibited significant antimalarial potential against CQ-sensitive and CQ-resistant strain of Plasmodium falciparum. Structure activity relationship has also been established based on outcomes of in vitro schizont inhibition assay. Compound 5u, (Z)-3-(1-(4-methylquinolin-2-yl)-3-p-tolyl-1H-pyrazol-4-yl)-1-p-tolylprop-2-en-1-one, was found to be the most potent among the series of synthetic analogues. In vivo, it demonstrated significant parasitemia suppression of 78.01% at a dose of 200 mg/kg against P. berghei in infected mice without any mortality in 7 days. In silico molecular docking study revealed that this compound 5u bound to the active site of cysteine protease falcipain-2 enzyme. Furthermore, in silico ADME studies, were also performed and physicochemical qualifications of the title compounds were determined. The biological outcomes of newer heterocyclic compounds may pave the new paths for researchers in development of potential antimalarial agents.

Spotlight on 4-substituted quinolines as potential anti-infective agents: Journey beyond chloroquine

Continued emerging resistance of pathogens against the clinically approved candidates and their associated limitations continuously demand newer agents having better potency with a more suited safety profile. Quinoline nuclei containing scaffolds of natural and synthetic origin have been documented for diverse types of pharmacological activities, and a number of drugs are clinically approved. In the present review, we unprecedentedly covered the biological potential of 4-substituted quinoline and elaborated a rationale for its special privilege to afford the significant number of approved clinical drugs, particularly against infectious pathogens. Compounds with 4-substituted quinoline are well documented for antimalarial activity, but in the last two decades, they have been extensively explored for activity against cancer, tuberculosis, and several other pathogens including viruses, bacteria, fungi, and other infectious pathogens. In the present study, the anti-infective spectrum of this scaffold is discussed against viruses, mycobacteria, malarial parasites, and fungal and bacterial strains, along with recent updates in this area, with special emphasis on the structure-activity relationship.

Investigation of tautomerism of 1,3,5-triazine derivative, stability, and acidity of its tautomers from density functional theory

Recent studies have identified N2,N4-bis(4-fluorophenethyl)-N6-(3-(dimethylamino)propyl)-1,3,5-triazine-2,4,6-triamine (1TZ(7,8,9)) as a potent, pure antagonist that inhibits thermosensory transient receptor potential vanilloid 1 channel (TRPV1) channel activity. This study provides theoretical data on the stability and acidity of the tautomers of this molecule. We show that this triazine can exist as three predominant tautomers (2TZ(5,7,8), 4TZ(3,7,9), 7TZ(1,8,9)). In the aqueous phase, equilibrium constants calculations show that only the tautomeric equilibria between 1TZ(7,8,9) and the three most stable triazines can be present which suggests that these three tautomeric equilibria would be the basis of 1TZ(7,8,9)'s biological activity.

Design and development of 1,3,5-triazine derivatives as protective agent against spinal cord injury in rat via inhibition of NF-ĸB

Spinal cord injury (SCI) is a chronic disease causing motor and sensory loss in the affected individuals. The SCI has a huge impact on the lives of patients that makes them susceptible to life-long disability. However, the current clinical modalities are ineffective to cope the aftermath of SCI. Thus, in the present study, we aimed to develop a series of 1,3,5-triazine derivatives as a protective agent against SCI. The molecules were developed by facile synthetic route and obtained in excellent yield. The compounds were tested for their efficacy to inhibit the transcription of NF-κB in RAW 264.7 cells, where they displayed mild to potent activity. Compound 8a was identified as most potent NF-κB inhibitor among the tested analogues. The effect of compound 8a was further scrutinized against the SCI injury in rats induced by contusion injury. It has been found that compound 8a improves motor function of rats together with reduction in inflammation and edema in spinal cord of rats. It also showed to inhibit oxidative stress and inflammation in the SCI rats. In a western blot analysis, after SCI induction, compound 8a inhibited NF-κB and its upstream regulator TLR4 in a dose-dependent manner. Collectively, our study provides a novel class of agent that provide protective action against SCI.

4-Aminosalicylic Acid-based Hybrid Compounds: Synthesis and In vitro Antiplasmodial Evaluation

Background:

Malaria is a deadly and infectious disease responsible for millions of death worldwide, mostly in the African region. The malaria parasite has developed resistance to the currently used antimalarial drugs, and it has urged researchers to develop new strategies to overcome this challenge by designing different classes of antimalarials.

Objectives:

A class of hybrid compounds containing 4-aminosalicylic acid moiety was prepared via esterification and amidation reactions and characterized using FTIR, NMR and LC-MS. In vitro antiplasmodial evaluation was performed against the asexual NF54 strain of P. falciparum parasites.

Methods:

In this research, known 4-aminoquinoline derivatives were hybridized with 4- aminosalicylic acid to afford hybrid compounds via esterification and amidation reactions. 4- aminosalicylic acid, a dihydrofolate compound inhibits DNA synthesis in the folate pathway and is a potential pharmacophore for the development of antimalarials.

Results:

The LC-MS, FTIR, and NMR analysis confirmed the successful synthesis of the compounds. The compounds were obtained in yields in the range of 63-80%. The hybrid compounds displayed significant antimalarial activity when compared to 4-aminosalicylic acid, which exhibited poor antimalarial activity. The IC50 value of the most potent hybrid compound, 9 was 9.54±0.57 nm.

Conclusion:

4-aminosalicylic has different functionalities, which can be used for hybridization with a wide range of compounds. It is a potential pharmacophore that can be utilized for the design of potent antimalarial drugs. It was found to be a good potentiating agent when hybridized with 4- aminoquinoline derivatives suggesting that they can be utilized for the synthesis of a new class of antimalarials.

Discovery of novel 1,3,5-triazine derivatives as potent inhibitor of cervical cancer via dual inhibition of PI3K/mTOR

This study describes the synthesis of novel 1,3,5-triazine derivatives as potent inhibitors of cervical cancer. The compounds were initially tested for inhibition of PI3K/mTOR, where they showed significant inhibitory activity. The top-ranking molecule (compound 6 h) was further tested against class I PI3K isoforms, such as PI3Kα, PI3Kβ, PI3Kγ and PI3Kδ, where it showed the most significant activity against PI3Kα. Compound 6 h was then tested for anti-cancer activity against triple-negative breast cancer cells (MDA-MB321), human breast cancer cells (MCF-7), human cervical cancer cells (HeLa) and human liver cancer cells (HepG2), and it showed the greatest potency against HeLa cells. The effects of compound 6 h were further evaluated against the HeLa cells, where it showed significant attenuation of cell viability by inducing cell cycle arrest in the G1 phase. Compound 6 h induced apoptosis and reduced migration and invasion of HeLa cells. Western blotting analysis showed that 6 h inhibited PI3K and mTOR with positive modulation of Bcl-2 and Bax levels in HeLa cells. The effects of compound 6 h were also investigated in a tumour xenograft mouse model, where it showed reduction of tumour volume and weight. It also inhibited the PI3K/Akt/mTOR signalling cascade in xenograft tumour tissues, as evidenced by western blotting analysis. The results of the present study suggest the possible utility of the designed 1,3,5-triazine derivative as a potent inhibitor of cervical cancer.

Discovery of novel 1,3,5-triazine as adenosine A2A receptor antagonist for benefit in Parkinson's disease

Parkinson's disease (PD) is a chronic neuro-degenerative ailment characterized by impairment in various motor and nonmotor functions of the body. In the past few years, adenosine A₂ A receptor (A₂ AR) antagonists have attracted much attention due to significant relief in PD. Therefore, in the current study, we intend to disclose the development of novel 1,3,5-triazines as A₂ AR antagonist. The radioligand binding and selectivity of analogs were tested in HEK293 (human embryonic kidney) and the cells were transfected with pcDNA 3.1(+) containing full-length human A₂ AR cDNA and pcDNA 3.1(+) containing full-length human A₁ R cDNA, where they exhibit selective affinity for A₂ AR. Molecular docking analysis was also conducted to rationalize the probable mode of action, binding affinity, and orientation of the most potent molecule (7c) at the active site of A₂ AR. It has been shown that compound 7c form numerous nonbonded interactions in the active site of A₂ AR by interacting with Ala59, Ala63, Ile80, Val84 Glu169, Phe168, Met270, and Ile274. The study revealed 1,3,5-triazines as a novel class of A₂ AR antagonists.

The Chemistry of Triazine Isomers: Structures, Reactions, Synthesis and Applications

Triazine is the six-membered heterocyclic ring containing three nitrogens, which replace the carbon-hydrogen unit in the benzene ring. Based on nitrogen position present in the ring system, it is categorized in three isomeric forms, i.e., 1, 2, 3-triazine (vicinal triazine), 1, 2, 4-triazine (asymmetrical triazine or isotriazine) and 1, 3, 5-triazine (symmetrical or s-triazine or cyanidine). Triazines have a weakly basic property. Their isomers have much weaker resonance energy than benzene structure, so nucleophilic substitution reactions are more preferred than electrophilic substitution reactions. Triazine isomers and their derivatives are known to play important roles possessing various activities in medicinal and agricultural fields such as anti-cancer, antiviral, fungicidal, insecticidal, bactericidal, herbicidal, antimalarial and antimicrobial agents.

Potent antibacterial activity of dihydydropyrimidine-1,3,5-triazines via inhibition of DNA gyrase and antifungal activity with favourable metabolic profile

The compounds were tested against panel of three Gram-positive, viz. Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and three Gram-negative bacterial strains viz. Pseudomonas aeruginosa, Escherichia coli, and Proteus vulgaris where they showed significant to moderate antibacterial activity. The compound also showed considerable antibiofilm activity against S. aureus and B. subtilis. The most potent compounds 7l and 7m found bacteriostatic in time-kill assay via inhibition of DNA gyrase enzyme and interacting with Glu58, Val130, Ile175 and Ile186 via numerous H-bonds as revealed by docking. In S. aureus-induced murine infection model, compound 7m showed dose-dependent reduction of viability of bacteria with maximum activity in 25 mg/kg treated group. The antifungal activity against human fungal pathogens was also estimated, where these compounds showed considerable inhibitory activity as compared to standard. The metabolic liability of compound 7m was determined using RS-Predictor and MetaPrint 2D React. The molecules were proved as effective antibacterial agent via inhibition of DNA gyrase as a mechanism together with significant antifungal activity.

Hybrid molecules with potential in vitro antiplasmodial and in vivo antimalarial activity against drug-resistant Plasmodium falciparum

Malaria is a tropical disease, leading to around half a million deaths annually. Antimalarials such as quinolines are crucial to fight against malaria, but malaria control is extremely challenged by the limited pipeline of effective pharmaceuticals against drug-resistant strains of Plasmodium falciparum which are resistant toward almost all currently accessible antimalarials. To tackle the growing resistance, new antimalarial drugs are needed urgently. Hybrid molecules which contain two or more pharmacophores have the potential to overcome the drug resistance, and hybridization of quinoline privileged antimalarial building block with other antimalarial pharmacophores may provide novel molecules with enhanced in vitro and in vivo activity against drug-resistant (including multidrug-resistant) P falciparum. In recent years, numerous of quinoline hybrids were developed, and their activities against a panel of drug-resistant P falciparum strains were screened. Some of quinoline hybrids were found to possess promising in vitro and in vivo potency. This review emphasized quinoline hybrid molecules with potential in vitro antiplasmodial and in vivo antimalarial activity against drug-resistant P falciparum, covering articles published between 2010 and 2019.

Malaria Hybrids: A Chronological Evolution

Malaria, an upsetting malaise caused by a diverse class of Plasmodium species affects about 40% of the world's population. The distress associated with it has reached colossal scales owing to the development of resistance to most of the clinically available agents. Hence, the search for newer molecules for malaria treatment and cure is an incessant process. After the era of a single molecule for malaria treatment ended, there was an advent of combination therapy. However, lately there had been reports of the development of resistance to many of these agents as well. Subsequently, at present most of the peer groups working on malaria treatment aim to develop novel molecules, which may act on more than one biological processes of the parasite life cycle, and these scaffolds have been aptly termed as Hybrid Molecules or Double Drugs. These molecules may hold the key to hitherto unknown ways of showing a detrimental effect on the parasite. This review enlists a few of the recent advances made in malaria treatment by these hybrid molecules in a sequential manner.

Recent Advances in the Discovery of Novel Antiprotozoal Agents

Parasitic diseases have serious health, social, and economic impacts, especially in the tropical regions of the world. Diseases caused by protozoan parasites are responsible for considerable mortality and morbidity, affecting more than 500 million people worldwide. Globally, the burden of protozoan diseases is increasing and is been exacerbated because of a lack of effective medication due to the drug resistance and toxicity of current antiprotozoal agents. These limitations have prompted many researchers to search for new drugs against protozoan parasites. In this review, we have compiled the latest information (2012-2017) on the structures and pharmacological activities of newly developed organic compounds against five major protozoan diseases, giardiasis, leishmaniasis, malaria, trichomoniasis, and trypanosomiasis, with the aim of showing recent advances in the discovery of new antiprotozoal drugs.

Combination Therapy Strategies for the Treatment of Malaria

Malaria is a vector- and blood-borne infection that is responsible for a large number of deaths around the world. Most of the currently used antimalarial therapeutics suffer from drug resistance. The other limitations associated with the currently used antimalarial drugs are poor drug bioavailability, drug toxicity, and poor water solubility. Combination therapy is one of the best approaches that is currently used to treat malaria, whereby two or more therapeutic agents are combined. Different combination therapy strategies are used to overcome the aforementioned limitations. This review article reports two strategies of combination therapy; the incorporation of two or more antimalarials into polymer-based carriers and hybrid compounds designed by hybridization of two antimalarial pharmacophores.

Quinazoline based 1,3,5-triazine derivatives as cancer inhibitors by impeding the phosphorylated RET tyrosine kinase pathway: Design, synthesis, docking, and QSAR study

The present research focused on designing a quinazoline skeleton, framed via 1,3,5-triazine derivatives (QBT) through field mapping and alignment studies. The QBT derivatives were synthesized via time- and cost-effective protocol. The 3D-QSAR study, computational physicochemical properties, and ADME calculation of the derivatives were performed to establish the affinity towards the biological system. Molecular docking in the adenosine triphosphate binding site of the RET tyrosine kinase domain (PDB ID: 7IVU) was studied to elucidate vital structural residues necessary for bioactivity. The derivatives were evaluated for anticancer potency against TPC-1 cells (thyroid cancer), MCF-7 cells (breast cancer), and one normal cell line (human foreskin fibroblasts) via 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide assay followed by an in ovo CAM assay. The entire series of derivatives (8a-o) showed mild to significant anticancer potency against the selected cancer cell lines.

Ligand-based Pharmacophore Model for Generation of Active Antidepressant- like Agents from Substituted 1,3,5 Triazine Class

INTRODUCTION

Although the transition of a lead candidate into a drug is currently structured by well-defined milestone, it is still most challenging and offers no guarantee in success to the end. In fact, ligand-based pharmacophore modeling has become a key motive force for retrieving potential leads across several therapeutic areas.

METHODS

An urgent need towards the development of novel antidepressant agents led us to generate a pharmacophore model from an existing 44 compounds dataset. The best model with one hydrophobic, two ring aromatic, and one positive ionization features was chosen on behalf of the correlation coefficient, sensitivity, specificity, yield of actives and accuracy measures using HypoGen module of Discovery Studio. In house library consisting of 10,000 substituted 1,3,5 triazine derivatives were shortlisted to select four insilico hits. All shortlisted compounds were synthesized and characterized by FTIR, 1H-& 13C-NMR spectroscopy and finally tested for antidepressant-like activity using behavioral models on rats viz. Forced Swim Test (FST) and Elevated Plus Maze (EPM).

RESULTS

Two shortlisted compounds with optimal fit values showed a significant decrease in the duration of immobility as compared to standard drug Imipramine in FST while time spent in open arm in enhanced in case of EPM.

Triazine Compound as Copolymerized Antibacterial Agent in Adhesive Resins

Abstract The aim of this study was to formulate and evaluate an experimental adhesive resin with the addition of 1,3,5-triacryloylhexahydro-1,3,5-triazine at different concentrations. Experimental adhesive resins were obtained by mixing 50% wt bisphenol A glycol dimethacrylate (BisGMA), 25% wt triethylene glycol dimethacrylate (TEGDMA), 25% wt 2-hydroxyethyl methacrylate (HEMA) and photoinitiator system. The triazine compound was added in 1, 2.5 and 5% wt to a base adhesive resin and one group remained with no triazine as control group. The experimental adhesive resins were analyzed for antibacterial activity (n=3), degree of conversion (n=3) and softening in solvent (n=3). Data distribution was evaluated by Kolmogorov-Smirnov test, paired t test, one-way ANOVA and Tukey’s with a 0.05 level of significance. All groups with added triazine compound showed antibacterial activity against Streptococcus mutans (p<0.05). All groups achieved more than 70% degree of conversion, but there was no difference in this chemical property (p>0.05). The initial Knoop hardness was higher in 2.5 and 5% wt groups (p<0.05) and both groups present lower percentage variation of Knoop hardness after solvent degradation. The present study formulated an antibacterial adhesive resin with a non-releasing agent able to copolymerize with the comonomeric blend, improving the restorative material’s properties.

Design, synthesis and antimalarial screening of some hybrid 4-aminoquinoline-triazine derivatives against pf-DHFR-TS

Existing antifolate antimalarial drugs have shown resistance due to the mutations at some amino acid positions of Plasmodium falciparum DHFR-TS. In the present study, to overcome this resistance, a new series of hybrid 4-aminoquinoline-triazine derivatives were designed and docked into the active site of Pf-DHFR-TS (PDB i.d. 1J3K) using validated CDOCKER protocol. Binding energy was calculated by applying CHARMm forcefield. Binding energy and the pattern of interaction of the docked compounds were analysed. Fifteen compounds were selected for synthesis based on their binding energy values and docking poses. Synthesized compounds were characterised by FTIR, (1)H NMR, (13)C NMR, mass spectroscopy and were screened for antimalarial activity against 3D7 strain of Plasmodium falciparum.

Sulfonamide-1,3,5-triazine–thiazoles: discovery of a novel class of antidiabetic agents via inhibition of DPP-4

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a novel class of antidiabetic drugs used for treating type 2 diabetes mellitus.