Antiviral activities of some synthesized methylsulfanyltriazoloquinazoline derivatives

Antiviral activity of some benzo[g]quinazolines against coxsackievirus B4: biological screening and docking study

BACKGROUND

Serotype coxsackievirus B (CVB) infection has been linked to viral myocarditis, dilated cardiomyopathy, meningitis, and pancreatitis in children and young adults. As of yet, no antiviral drug has been authorized for the treatment of coxsackievirus infection. Therefore, there is perpetual demand for new therapeutic agents and the improvement of existing ones. Benzo[g]quinazolines, the subject of several well-known heterocyclic systems, have risen to prominence and played a significant role in the development of antiviral agents, particularly those for anti-coxsackievirus B4 infection.

METHODS

This study investigated the cytotoxicity of the target benzo[g]quinazolines (1-16) in the BGM cells line as well as their anti-coxsackievirus B4 activity. Determination of CVB4 titers using a plaque assay.

RESULTS

Most of the target benzoquinazolines exhibited antiviral activity, however, compounds 1-3 appeared to be the most effective (reduction percentages of 66.7, 70, and 83.3%, respectively). The binding mechanisms and interactions of the three most active 1-3 with the constitutive amino acids in the active site of the multi-target of coxsackievirus B4 (3Clpro and RdRp) targets were also investigated using molecular docking.

CONCLUSION

The anti coxsackievirus B4 activity has resulted, and the top three active benzoquinazolines (1-3) have bonded to and interacted with the constitutive amino acids in the active region of the multi-target coxsackievirus B4 (RdRp and 3Clpro). Further research is required in the lab. to determine the exact benzoquinazolines mechanism of action.

Biological Investigation of 2-Thioxo-benzo[g]quinazolines against Adenovirus Type 7 and Bacteriophage Phi X174: An In Vitro Study

Mortality and morbidity caused by viruses are a global health problems. Therefore, there is always a need to create novel therapeutic agents and refine existing ones to maximize their efficacy. Our lab has produced benzoquinazolines derivatives that have proven effective activity as antiviral compounds against herpes simplex (HSV 1 and 2), coxsackievirus B4 (CVB4), and hepatitis viruses (HAV and HCV). This in vitro study was aimed at investigating the effectiveness of benzoquinazoline derivatives 1-16 against adenovirus type 7 and bacteriophage phiX174 using a plaque assay. The cytotoxicity against adenovirus type 7 was also performed in vitro, using a MTT assay. Most of the compounds exhibited antiviral activity against bacteriophage phiX174. However, compounds 1, 3, 9, and 11 showed statistically significant reductions of 60-70% against bacteriophage phiX174. By contrast, compounds 3, 5, 7, 12, 13, and 15 were ineffective against adenovirus type 7, and compounds 6 and 16 had remarkable efficacy (50%). Using the MOE-Site Finder Module, a docking study was carried out in order to create a prediction regarding the orientation of the lead compounds (1, 9, and 11). This was performed in order to investigate the activity of the lead compounds 1, 9, and 11 against the bacteriophage phiX174 by locating the ligand-target protein binding interaction active sites.

Significant pharmacological activities of benzoquinazolines scaffold

Benzoquinazolines, the essential constituents of numerous well-known heterocyclic systems, have occupied a prominent position and played a significant part in the synthesis of various pharmaceutical compounds. The wide range of pharmacological effects attributed to benzoquinazolines has been the subject of extensive study. These include their roles as anticancer, antimicrobial, anti-monoamine oxidase, anticonvulsant, antiviral, antinociceptive, antioxidant, antineoplastic, antituberculosis, antiplatelet, and antiphlogistic agents. This work provides an attempt at a literature review of the pharmacological activities of benzoquinazoline derivatives, including an up-to-date account of recent research findings, and suggests avenues for future exploration in the pursuit of more potent and specific analogues for a wide range of biological targets using this platform.

DFT Calculation, Hirshfeld Analysis and X-Ray Crystal Structure of Some Synthesized N-alkylated(S-alkylated)-[1,2,4]triazolo[1,5-a]quinazolines

The present work aimed to synthesize 2-methylthio-triazoloquinazoline derivatives and study their X-ray, NMR, DFT and Hirshfeld characteristics. The cyclocondensation of dimethyl-N-cyanodithiocarbonate with 2-hydrazinobenzoic acid hydrochloride resulted in an intermediate, 2-methylthio-[1,2,4]triazolo[1,5-a]quinazolin-5-one (A), which upon treatment with phosphorus pentasulfide, transformed into the 2-methylthio-[1,2,4]triazolo[1,5-a]quinazolin-5-thione (B). Reaction of 2-methylthio-triazoloquinazolines (A&B) with alkyl halides (allyl bromide and ethyl iodide) in basic medium afforded 4-allyl-2-methylthio-[1,2,4]triazolo[1,5-a]quinazolin-5-one (1; N-alkylated) and 5-ethylthio-2-methylthio-[1,2,4]triazolo[1,5-a]quinazoline (2; S-alkylated), respectively. Their molecular and supramolecular structures were presented. Unambiguously, the molecular structures of 1 and 2 were confirmed via NMR and single-crystal X-ray diffraction. The resulting findings confirmed the structures of 1 and 2 and determined their crystalized system (monoclinic system; P21/n space group). Hirshfeld analysis of 1 revealed the importance of the significantly short O···H (6.7%), S···S (1.2%) and C···C (2.8%); however, the short H···H (42.6%), S···H (16.3%) and C···C (4.3%) were showed in 2 by intermolecular interactions in the molecular packing. The 1,2,4-triazoloquinzolines (1&2) were anticipated to be relatively polar compounds with net dipole moments of 2.9284 and 4.2127 Debye, respectively. The molecular electrostatic potential, atomic charge distribution maps and reactivity descriptors for 1 and 2 were also determined. The calculated nuclear magnetic resonance spectra of the targets 1 and 2 were well correlated with the experimental data.

An overview of triazoloquinazolines: Pharmacological significance and recent developments

Nitrogen heterocyclic rings have participated to constitute most of the drugs and several pharmacologically related compounds. The existence of such hetero atoms/groups in heterocyclic systems privileged specificities in their biological objectives. Particularly, quinazoline and triazole are biologically imperative platforms known to be linked with various pharmacological activities. Some of the prominent pharmacological responses ascribed to these systems are analgesic, antiinflammatory, anticonvulsant, hypnotic, antihistaminic, antihypertensive, anticancer, antimicrobial, antitubercular, antiviral and antimalarial activities. This diversity in the pharmacological outputs for both triazole and quinazoline systems has encouraged the medicinal chemistry researchers to create several chemical routes aiming at the incorporation of two rings in one molecule named triazoloquinazoline system. This system has shown multiple potential activities against numerous targets. Correlation the specific structural features of triazoloquinazoline system with its pharmacological purposes has successively been achieved by performing several pharmacological examinations and structure-activity relationship studies. The development of triazoloquinazoline derivatives and the understanding of their pharmacological targets offer opportunities for novel therapeutics. This review mainly emphases on the medicinal chemistry aspects of triazoloquinazolines including synthesis, reactivity, biological activity and structure activity relationship studies (SARs). Moreover, this review collates literature reported by researchers on triazoquinazolines and provides detailed attention on their analogs pharmacological activities in the perspective of drug development and discovery.

Synthesis and antioxidant activity of 2-methylthio-pyrido[3,2-e][1,2,4] triazolo[1,5-a]pyrimidines

A series of 2-methylthio-pyrido-triazolopyrimidines (1-17) were prepared by the reaction of dimethyl-N-cyanoimidodithiocarbonate with hydrazinopyridine carboxylic acid as starting reactants. Their chemical structures were affirmed with HREI-MS, IR and NMR analyses. The target compounds (1-17) were evaluated for their antioxidant activity using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging, ferric reduction antioxidant power (FRAP) and reducing power capability (RPC). The results revealed that some pyrido-triazolopyrimidines showed good activity as antioxidant agents, in particular, compounds 12 and 15 were found to possess good antioxidant activity. Butylated hydroxyl toluene (BHT) was used as reference drug.

Anti-HAV evaluation and molecular docking of newly synthesized 3-benzyl(phenethyl)benzo[g]quinazolines

Synthesized 3-benzyl(phenethyl)benzo[g]quinazolines (1-17) were evaluated in vitro to determine their effects against the anti-hepatitis A virus (HAV) using a cytopathic effect inhibition assay. Of the synthesized compounds, 16 and 17 showed considerably high anti-HAV activity, as indicated by their EC₅₀ values of 27.59 and 18 μM, respectively, when compared to that of amantadine (37.3 μM), the standard therapeutic agent. In addition, they exhibited low cytotoxicity as indicated by their CC₅₀ values, 290.63 and 569.45 μM, respectively. Compounds 1, 2, and 5 exhibited remarkable activity compared to the active compounds (16, 17) and amantadine. The selectivity index (SI) values were calculated and applied as a parameter for classifying the activity of the targets. In addition, molecular docking was performed to rationalize the SAR of the target compounds and analyze the binding modes between the docked-selected compounds and amino acid residues in the active site of the HAV-3C proteinase enzyme.

Molecular docking study and antiviral evaluation of 2-thioxo-benzo[g]quinazolin-4(3H)-one derivatives

BACKGROUND

The persistent appearance of viral strains that causes a resistant viral infection has led to continuous trials for the design and development of novel antiviral compounds. Benzoquinazoline compounds have been reported to exhibit an interesting antiviral activity. This work aims to study and evaluate the antiviral activity of a newly prepared 2-thioxo-benzo[g]quinazolin-4(3H)-one series against herpes simplex (HSV-1 & 2) and coxsackievirus (CVB4).

METHODS

The antiviral activity was performed using the MTT assay, in which Vero cells (obtained from the American Type Culture Collection, ATCC) were propagated in fresh Dulbecco's Modified Eagle's Medium (DMEM) and challenged with 10(4) doses of the virus. Thereafter, the cultures were treated simultaneously with two-fold serial dilutions of the tested compound and incubated at 37 °C for 48 h. Molecular docking studies were done on the CVB4 2A proteinase enzyme using Molegro Virtual Docker software.

RESULTS

The cytotoxicity (CC50), effective concentration (EC50) and the selectivity index (SI) values were determined. Based on their EC50 values, a number of the investigated compounds demonstrated weak to moderate activity relative to their parents. Accordingly, compounds 5-9, 11, 15-18, 21, 22, 24, 25, 27 and 28 were active against CVB4, and compounds 5 and 24 were active against HSV-1 and 2 in comparison to ribavirin and acyclovir, which were used as reference drugs.

CONCLUSION

The obtained results gave us some useful insights about the characteristic requirements for future trials to build up and design more active and selective antiviral 2-thioxo-benzo[g]quinazolin-4(3H)-one agents.Graphical abstractCompound 24 superimposed with Ribavirin in CV B4 2A Proteinase enzyme (PDB: 1Z8R) active site.