[Assessment of the antiviral activity of 2HCl*H-His-Rim compound compared to the anti-influenza drug Arbidol for influenza caused by A/duck/Novosibirsk/56/05 (H5N1) (Influenza A virus, Alphainfluenzavirus, Orthomyxoviridae).]

Compounds based on Adamantyl-substituted Amino Acids and Peptides as Potential Antiviral Drugs Acting as Viroporin Inhibitors

The discussion has revolved around the derivatives of amino acids and peptides containing carbocycles and their potential antiviral activity in vitro against influenza A, hepatitis C viruses, and coronavirus. Studies conducted on cell cultures reveal that aminoadamantane amino acid derivatives exhibit the capacity to hinder the replication of viruses containing viroporins. Furthermore, certain compounds demonstrate potent virucidal activity with respect to influenza A/H5N1 and hepatitis C virus particles. A conceptual framework for viroporin inhibitors has been introduced, incorporating carbocyclic motifs as membranotropic carriers in the structure, alongside a functional segment comprised of amino acids and peptides. These components correspond to the interaction with the inner surface of the channel's pore or another target protein.

[Antiviral properties of synthetic histidine derivatives containing membranotropic volumetrical carbocycles in their molecule against SARS-CoV-2 virus in vitro]

INTRODUCTION

Currently, low molecular-weight compounds are being developed as potential inhibitors of CoVs replication, targeting various stages of the replication cycle, such as major protease inhibitors and nucleoside analogs. Viroporins can be alternative protein targets. The aim of this study is to identify antiviral properties of histidine derivatives with cage substituents in relation to pandemic strain SARS-CoV-2 in vitro.

MATERIALS AND METHODS

Combination of histidine with aminoadamantane and boron cluster anion [B10H10]2 (compounds IIV) was carried out by classical peptide synthesis. Compound were identified by modern physicochemical methods. Antiviral properties were studied in vitro on a monolayer of Vero E6 cells infected with SARS-CoV-2 (alpha strain) with simultaneous administration of compounds and virus.

RESULTS

Derivatives of amino acid histidine with carbocycles and boron cluster were synthesized and their antiviral activity against SARS-CoV-2 was studied in vitro. Histidine derivatives with carbocycles and [B10H10]2 have the ability to suppress virus replication. The solubility of substances in aqueous media can be increased due to formation of hydrochloride or sodium salt.

DISCUSSION

2HCl*H-His-Rim (I) showed some effect of suppressing replication of SARS-CoV-2 at a viral load of 100 doses and concentration 31.2 g/ml. This is explained by the weakly basic properties of compound I.

CONCLUSION

The presented synthetic compounds showed moderate antiviral activity against SARS-CoV-2. The obtained compounds can be used as model structures for creating new direct-acting drugs against modern strains of coronaviruses.

Physiologically Active Compounds Based on Membranotropic Cage Carriers–Derivatives of Adamantane and Polyhedral Boron Clusters (Review)

Data on compounds based on cage structures―boron clusters (polyhedral boron hydrides, carboranes, metallacarboranes) and compounds of the adamantane series, which possess physiological activity, have been generalized. The main emphasis is placed on the antiviral activity of the compounds. The mechanism of the possible action of the replication inhibitors of influenza A virus strains is considered, the molecular model of viroporin inhibitors is discussed. The proposed model consists of a cage hydrophobic core that performs the function of a membranotropic carrier (a boron cluster or adamantane fragment), into which physiologically active functional groups are introduced. The relationship between the structure of the cage compound with the introduced substitute and the biologically active properties of this molecular structure has been analyzed.

Studying the Effect of Amino Acid Substitutions in the M2 Ion Channel of the Influenza Virus on the Antiviral Activity of the Aminoadamantane Derivative In Vitro and In Silico

Purpose: The aminoadamantane derivative of L-histidyl-1-adamantayl ethylamine hydrochloride (HCl*H-His-Rim) has showed a high inhibition level against influenza A virus strains in vitro. The aim of this work is to search and establish evidence of the direct effect of the drug on influenza A virus proton channel M2.

Methods: The compound HCl*H-His-Rim was obtained by classical peptide synthesis methods. Influenza A virus mutants of A/PuertoRico/8/34(H1N1) strain were obtained by reverse genetics methods. The mutant samples of the virus were cultured on chicken embryos with a virus titer in the hemagglutination test. ELISA was carried out on Madin-Darby canine kidney (MDCK) monolayer cells when multiplying the virus 10^-4-10^-6. The binding stability of HCl*H-His-Rim was compared to those of M2 (S31N) and M2 (S31N_A30T) channels by molecular dynamic (MD) modeling. The calculation was performed taking into account the interaction with the model lipid bilayer (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) in the presence of water molecules in accordance with the three-center model.

Results: It was found that HCl*H-His-Rim is a direct action drug against influenza A. The most likely conformation of drug binding to target protein has been shown. It has been found that the A30T mutation reduces the binding energy of the drug, and the results obtained in vitro have confirmed the data calculated in silico.

Conclusion: The mechanism of action of HCl*H-His-Rim is directly related to the suppression of the function of the proton channel M2 of influenza A virus.