Relationship between structure of benzimidazole derivatives and selective virus inhibitory activity. Inhibition of poliovirus multiplication and cytopathic effects by 2-(alpha-hydroxybenzyl)-benzimidazole, and its 5-chloroderivative

New cyclic arylguanidine scaffolds as a platform for development of antimicrobial and antiviral agents

According to WHO, infectious diseases are still a significant threat to public health. The combine effects of antibiotic resistance, immunopressure, and mutations within the bacterial and viral genomes necessitates the search for new molecules exhibiting antimicrobial and antiviral activities. Such molecules often contain cyclic guanidine moiety. As part of this work, we investigated the selected antimicrobial and antiviral activity of compounds from the cyclic arylguanidine group. Molecules were designed using molecular modeling and obtained using microwave radiation (MW) and sonochemical ()))) methods, in accordance with the previously developed pathways. The obtained compounds were screened for the ability to inhibit the growth of Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, and Cryptococcus neoformans. The capacity to block the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into the host cell was probed using a bioluminescence immunoassay. The cytotoxicity and hemolytic properties of the most active molecules were also evaluated. The N-[2-(naphthalen-1-yl)ethyl]-5-phenyl-1,4,5,6-tetrahydro-1,3,5-triazin-2-amine 12j showed a high inhibition of Staphylococcus aureus and Cryptococcus neoformans (MIC ≤ 0.25 µg/mL), with no cytotoxic nor hemolytic effect (CC50, HC10 > 32 µm/mL). The CO-ADD platform identified many potentially useful molecules. A particularly rich population was examined in the database of the N.D. Zelinsky Institute of Organic Chemistry, in which 2517 active molecules (MIC ≤ 32 mg/mL) were found, of which about 10% are active at very low concentrations (MIC ≤ 1 mg/mL).

Eco-friendly methods of synthesis and preliminary biological evaluation of sulfonamide derivatives of cyclic arylguanidines

The chemotype of arylsulfonamide derivatives of cyclic arylguanidines is a source of molecules with valuable biological activities, including antimicrobial and antitumor properties. The methods of the synthesis presented in the literature are characterized with low selectivity and high environmental nuisance. In this publication, we present a developed alternative and earlier undescribed pathway C, for the synthesis of arylsulfonamide derivatives of cyclic arylguanidines (N-(1H-arylimidazol-2-yl)arylsulfonamides and N-(1,4-dihydroquinazolin-2-yl)arylsulfonamides), including reaction between 2-(methylsulfanyl)-benzimidazole or 2-(methylsulfanyl)-3,4-dihydroquinazoline with arylsulfonamides. We also optimized previously reported methods; A (reaction of 2-aminobenzimidazole or 2-amino-3,4-dihydroquinazoline with arylsulfonyl chlorides) and B (reaction of dimethyl-(arylsulfonyl)carbonodithioimidate with aryldiamines). The conducted research allowed achieving two independent ecological and quick methods of obtaining the desired products. We used ecological methods of ultrasound-assisted or microwave synthesis, solvent-free reactions and a"green" reaction environment. In both pathways, it has proven advantageous to use H₂O as the solvent and K₂CO₃ (1 or 3 equivalent) as the basic agent. In the sonochemical variant, the efficiency reached B: 37-89 %, C: 90 % in 60 min (P = 80 W and f = 40 kHz), while in the microwave synthesis it was B: 38-74 %, C: 63-85 % in 0.5-4 min (P = 50 W). Path A led to a complementary substitution product (i.e. 1-(arylsulfonyl)-1H-benzimidazol-2-amine or 1-(arylsulfonyl)-1,4-dihydroquinazolin-2-amine). We obtained a small group of compounds that were tested for cytotoxicity. The 10f (N-(1,4-dihydroquinazolin-2-yl)naphthalene-1-sulfonamide) showed cytotoxic activity towards human astrocytoma cell line 1321 N1. The calculated IC₅₀ value was 8.22 µM at 24 h timepoint (doxorubicin suppressed 1321 N1 cell viability with IC₅₀ of 1.1 µM). The viability of the cells exposed to 10f for 24 h dropped to 48.0 % compared to vehicle control, while the cells treated with doxorubicin experienced decline to 47.5 %. We assessed its potential usefulness in pharmacotherapy in the ADMET study, confirming its ability to cross the blood-brain barrier (Pe = 5.0 ± 1.5 × 10^-6 cm/s) and the safety of its potential use in terms of DDI and hepatotoxicity.

Antiviral activity of benzotriazole derivatives. 5-[4-(Benzotriazol-2-yl)phenoxy]-2,2-dimethylpentanoic acids potently and selectively inhibit Coxsackie Virus B5

A library of 64 benzotriazole derivatives (17 of which were [4-(benzotriazol-2-yl)phenoxy]alkanoic acids) were screened for antiviral activity against a panel of twelve DNA and RNA viruses. Twenty-six compounds (12 of which were [4-(benzotriazol-2-yl)phenoxy]alkanoic acids) displayed activity against one or more viruses. CVB-5, RSV, BVDV, Sb-1 and YFV were, in decreasing order, the more frequently and effectively affected viruses; DENV-2, WNV, HIV-1 and Reo-1 were only occasionally and modestly affected, while the remaining viruses were not affected by any of the tested compounds. Worth of note were compounds 33 and 35; the former for the activity against Sb-1 (EC50=7 μM) and the latter for the large spectrum of activity including six viruses with a mean EC50=12 μM. Even more interesting were the alkanoic acids 45-48 and 50-57 for their activity against RSV and/or CVB-5. In particular, compound 56 displayed a potent and selective activity against CVB-5 with EC50=0.15 μM and SI=100, thus representing a valuable hit compound for the development of antiviral agents for the treatment of human pathologies related to this virus.

Synthesis, Molecular Modeling, and Biological Activity of Zinc(II) Salts with 1,4-Bis(benzimidazol-2-yl)benzene

Zinc(II) halides and perchlorate react with 1,4-bis(benzimidazol-2-yl)benzene (L) in 1 : 2 molar ratio in n-butanol/2-methoxy ethanol (10 mL) at refluxing temperature to produce white/pale yellow-colored complexes of the formulae [ZnCl2L]H2O, [ZnBr2L]3H2O, and [Zn(OClO3)2L]HOCH2CH2CH2CH3. Zinc(II) iodide also reacts with L in 1 : 2 molar ratio in n-butanol (HOCH2CH2CH2CH3) to yield white-colored complex of the formula [ZnL2(OCH2CH2CH2CH3)2]. The complexes were characterized by elemental analysis, molar conductance measurements, thermal analysis, and IR,1H-,13C-NMR spectral studies. The complexes showed significant anthelmintic activity. The minimum energy configuration has been obtained for the zinc complexes using molecular modeling Pro Plus; a tool developed by ChemSW, inc, USA.

Mutations in the 2C region of poliovirus responsible for altered sensitivity to benzimidazole derivatives

MRL-1237, [1-(4-fluorophenyl)-2-(4-imino-1,4-dihydropyridin-1-yl) methylbenzimidazole hydrochloride], is a potent and selective inhibitor of the replication of enteroviruses. To reveal the target molecule of MRL-1237 in viral replication, we selected spontaneous MRL-1237-resistant poliovirus mutants. Of 15 MRL-1237-resistant mutants obtained, 14 were cross-resistant to guanidine hydrochloride (mrgr), while 1 was susceptible (mrgs). Sequence analysis of the 2C region revealed that the 14 mrgr mutants contained a single nucleotide substitution that altered an amino acid residue from Phe-164 to Tyr. The mrgs mutant, on the other hand, contained a substitution of Ile-120 to Val. Through the construction of a cDNA-derived mutant, we confirmed that the single mutation at Phe-164 was really responsible for the reduced susceptibility to MRL-1237. MRL-1237 inhibited poliovirus-specific RNA synthesis in HeLa cells infected with a wild strain but not with an F164Y mutant. We furthermore examined the effect of mutations of the 2C region on the drug sensitivity of cDNA-derived guanidine-resistant and -dependent mutants. Two guanidine-resistant mutants were cross-resistant to MRL-1237 but remained susceptible to another benzimidazole, enviroxime. Either MRL-1237 or guanidine stimulated the viral replication of two guanidine-dependent mutants, but enviroxime did not. These results indicate that MRL-1237, like guanidine, targets the 2C protein of poliovirus for its antiviral effect.

Spectrum and characteristics of the virus inhibitory action of 2-(alpha-hydroxybenzyl)-benzimidazole

2-(α-Hydroxybenzyl)-benzimidazole (HBB) inhibited the cytopathic effects of the following enteroviruses: polio 1 to 3; Coxsackie A9; Coxsackie B 1 to 6; and ECHO virus types 1 to 9, 11 to 21, and 24 to 27. The following enteroviruses were not inhibited: Coxsackie A types 7, 11, 13, 16, and 18; and ECHO types 22, 23, and 28. Other HBB-insusceptible viruses were: arbor B and C, reo 1 to 3; adeno 2 to 4; influenza B; para-influenza 2 and 3; mumps; herpes simplex, and vaccinia. HBB had no inactivating effect on viral infectivity, but rather inhibited some intracellular step in the reproductive cycle of susceptible viruses. With all viruses examined, inhibition of viral cytopathic effects appeared to be due to inhibition of virus multiplication. Virus inhibition by HBB was demonstrable in monkey kidney, HeLa, and ERK cells. HBB-susceptible viruses varied quantitatively in their susceptibility to the compound, and different strains of the same virus also exhibited varying susceptibility. No relationship was found between attenuation of polioviruses and their susceptibility to the compound. After passage of HBB-susceptible enteroviruses in the presence of the compound, virus populations with lowered susceptibility to HBB were obtained. At virus inhibitory concentrations, HBB did not affect the morphology of cells, nor the following cellular metabolic activities: oxygen uptake; glucose utilization; lactic acid production; and incorporation of adenosine into RNA, and of alanine into proteins. The rates of multiplication of HeLa and ERK. cells were not significantly altered by HBB at virus inhibitory concentrations.

Benzimidazole derivatives: new enhancers of influenza virus multiplication

The enhancing activity of 5-methyl-2-D-ribobenzimidazole on influenza B (Lee) virus yield in chorioallantoic membranes from 10-day old embryonated eggs was compared with that of eight other polyhydroxyalkyl-benzimidazoles. No marked differences in activity were noted with the following six derivatives: 5,6-dimethyl-2-D-ribo; 2-D-gluco; 5-methyl-2-D-gluco; 5,6-dimethyl-2-D-gluco; 5-methyl-2-D-galacto; and 5-methyl-2-L-rhamno. None caused morphological damage to the membranes at a concentration of 3.5 mM. The solubility of the 5-methyl-2-D-arabo and 5-methyl-2-D-manno derivatives was too low to permit quantitative comparisons, but both were active and nontoxic at a concentration of 1.75 mM. 5-Hydroxy-1-methylbenzimidazole and 5-methoxy-1-methylbenzimidazole are more active than 5-methyl-2-D-ribobenzimidazole both with respect to specific activity and maximal enhancement at the highest tolerated dose. The hydroxyl substituent is superior to the methoxyl grouping. Substitution at position 5 is superior to substitution at position 6 with respect to the tolerated dose level and therefore the maximal effect obtainable, but the 6-hydroxy-1-methyl derivative showed the highest specific activity. 5-Methoxy-1-methylbenzimidazole increases the yield to a comparable extent as measured by infectivity and hemagglutination titrations. The responses of membranes from individual chicken embryos to the enhancing action of 5-methoxy-1-methylbenzimidazole and 5-methyl-2-D-ribobenzimidazole are similar. 5-Methoxy-1-methylbenzimidazole restores the capacity of membranes from older chicken embryos to produce a large amount of virus after a small inoculum. This derivative increases the yield of virus in membranes treated before infection only. Maximal enhancement is obtained with prolonged treatment, starting before, and continuing after infection. 5-Methoxy-1-methyl-benzimidazole increases the yield of virus from COFAL-negative embryos in which the control yield is very low. Combined treatment with moderate doses of 5-methoxy-1-methylbenzimidazole and 5-methyl-2-D-ribobenzimidazole gives an additive effect.

Inhibition of enterovirus cytopathic effects by 2-(alpha-hydroxybenzyl)-benzimidazole

Bablanian, Rostom (The Rockefeller University, New York, N.Y.), Hans J. Eggers, and Igor Tamm. Inhibition of enterovirus cytopathic effects by 2-(alpha-hydroxybenzyl)-benzimidazole. J. Bacteriol. 91:1289-1294. 1966.-2-(alpha-Hydroxybenzyl)-benzimidazole (HBB), a specific inhibitor of enterovirus multiplication, markedly delayed the development of cytopathological changes induced by echovirus 12 or coxsackievirus B4 in monkey kidney cells, but did not prevent the ultimate degeneration of infected cells, even though virus multiplication was inhibited. The study of the development of viral cytopathic effects was facilitated by the use of antiviral immune serum, which restricted the infection to those cells which became infected by the inoculated virus and thereby established single-cycle conditions. With echovirus 12 and coxsackievirus B4 not all cells could be infected initially, even when cultures were inoculated at input multiplicities in excess of 100 plaque-forming units per cell.