Synthesis and Inhibition of Influenza H1N1 Virus by Indolo-Glycyrrhetic Acid Cyanoesters

Two new indolo-glycyrrhetic acid derivatives containing cyano-substitutent at C30 have been synthesized, and their anti-influenza activity has been evaluated in vitro. The resulting data demonstrated moderate inhibitory activity against the H1N1 virus with IC50 29 and 23 μM, respectively. The value of SI 18 and 21 confirm low toxicity and potential of new compounds for following research and development of new biological agents

Design of 4-Substituted Sulfonamidobenzoic Acid Derivatives Targeting Coxsackievirus B3

A series of novel 4-substituted sulfonamidobenzoic acid derivatives was synthesized as the structural evolution of 4-(4-(1,3-dioxoisoindolin-2-yl)phenylsulfonamido)benzoic acid, which is the known inhibitor of the enterovirus life cycle. Antiviral properties of prepared compounds were evaluated in vitro using phenotypic screening and viral yield reduction assay. Their capsid binding properties were verified in thermostability assay. We identified two new hit-compounds (4 and 7a) with high activity against the coxsackievirus B3 (Nancy, CVB3) strain with potencies (IC50 values of 4.29 and 4.22 μM, respectively) which are slightly superior to the reference compound 2a (IC50 5.54 μM). Both hits changed the heat inactivation of CVB3 in vitro to higher temperatures, suggesting that they are capsid binders, as 2a is. The results obtained can serve as a basis for further development of the lead compounds for novel drug design to combat enterovirus infection

Molecular Modeling of Viral Type I Fusion Proteins: Inhibitors of Influenza Virus Hemagglutinin and the Spike Protein of Coronavirus

The fusion of viral and cell membranes is one of the basic processes in the life cycles of viruses. A number of enveloped viruses confer fusion of the viral envelope and the cell membrane using surface viral fusion proteins. Their conformational rearrangements lead to the unification of lipid bilayers of cell membranes and viral envelopes and the formation of fusion pores through which the viral genome enters the cytoplasm of the cell. A deep understanding of all the stages of conformational transitions preceding the fusion of viral and cell membranes is necessary for the development of specific inhibitors of viral reproduction. This review systematizes knowledge about the results of molecular modeling aimed at finding and explaining the mechanisms of antiviral activity of entry inhibitors. The first section of this review describes types of viral fusion proteins and is followed by a comparison of the structural features of class I fusion proteins, namely influenza virus hemagglutinin and the S-protein of the human coronavirus

Activity of Ingavirin (6-[2-(1H-Imidazol-4-yl)ethylamino]-5-oxo-hexanoic Acid) Against Human Respiratory Viruses in in Vivo Experiments

Respiratory viral infections constitute the most frequent reason for medical consultations in the World. They can be associated with a wide range of clinical manifestations ranging from self-limited upper respiratory tract infections to more devastating conditions such as pneumonia. In particular, in serious cases influenza A leads to pneumonia, which is particularly fatal in patients with cardiopulmonary diseases, obesity, young children and the elderly. In the present study, we show a protective effect of the low-molecular weight compound Ingavirin (6-[2-(1H-imidazol-4-yl)ethylamino]-5-oxohexanoic acid) against influenza A (H1N1) virus, human parainfluenza virus and human adenovirus infections in animals. Mortality, weight loss, infectious titer of the virus in tissues and tissue morphology were monitored in the experimental groups of animals. The protective action of Ingavirin was observed as a reduction of infectious titer of the virus in the lung tissue, prolongation of the life of the infected animals, normalization of weight dynamics throughout the course of the disease, lowering of mortality of treated animals compared to a placebo control and normalization of tissue structure. In case of influenza virus infection, the protective activity of Ingavirin was similar to that of the reference compound Tamiflu. Based on the results obtained, Ingavirin should be considered as an important part of anti-viral prophylaxis and therapy

Novel [1,2,4]triazolo[3,4-<i>b</i>][1,3,4]thiadiazine and [1,2,4]triazolo[3,4-<i>b</i>][1,3,4]thiadiazepine Derivatives: Synthesis, Anti-Viral In Vitro Study and Target Validation Activity

This study of the interaction system of binucleophilic 3-substituted 4-amino-4H-1,2,4-triazole-5-thiols and 3-phenyl-2-propynal made it possible to develop a new approach to synthesis of such isomeric classes as 7-benzylidene-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine and 8-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazepine. Among the 20 compounds studied in vitro against influenza A/Puerto Rico/8/34 (H1N1) virus, half of them demonstrated selectivity index (SI) of 10 or higher and one of them (4-((3-phenylprop-2-yn-1-yl)amino)-4H-1,2,4-triazole-3-thiol) possessed the highest (SI > 300). Docking results and values showed that the preferred interactant for our ligands was M2 proton channel of the influenza A virus. Protein-ligand interactions modeling showed that the aliphatic moiety of ligands could negatively regulate target activity level

Anti-influenza activity of diazaadamantanes combined with monoterpene moieties

The antiviral activity of several diaza-adamantanes containing monoterpenoid moieties against a rimantadine-resistant strain of the influenza A/Puerto Rico/8/34 (H1N1) virus was studied. Hetero-adamantanes containing monoterpene moieties at the aminal position of the heterocycle were found to exhibit lower activity compared to compounds with a diaza-adamantane fragment and a monoterpene moiety linked via an amino group at the 6-position of the hetero-adamantane ring. The highest selectivity index (a ratio of the 50% cytotoxic concentration to the 50% inhibitory concentration) out of 30 was observed for compound 8d, which contains a citronellal monoterpenoid moiety. Diaza-adamantane 8d was superior to its adamantane-containing analog 5 both in its anti-influenza activity and selectivity. Furthermore, 8d has more balanced physicochemical properties than 5, making the former a more promising drug candidate. Modelling these compounds against an influenza virus M2 ion channel predicted plausible binding modes to both the wild-type and the mutant (S31N)

Water-Soluble Fullerene C₆₀ Derivatives Are Effective Inhibitors of Influenza Virus Replication

The influenza virus genome features a very high mutation rate leading to the rapid selection of drug-resistant strains. Due to the emergence of drug-resistant strains, there is a need for the further development of new potent antivirals against influenza with a broad activity spectrum. Thus, the search for a novel, effective broad-spectrum antiviral agent is a top priority of medical science and healthcare systems. In this paper, derivatives based on fullerenes with broad virus inhibiting activities in vitro against a panel of influenza viruses were described. The antiviral properties of water-soluble fullerene derivatives were studied. It was demonstrated that the library of compounds based on fullerenes has cytoprotective activity. Maximum virus-inhibiting activity and minimum toxicity were found with compound 2, containing residues of salts of 2-amino-3-cyclopropylpropanoic acid (CC50 > 300 µg/mL, IC50 = 4.73 µg/mL, SI = 64). This study represents the initial stage in a study of fullerenes as anti-influenza drugs. The results of the study lead us conclude that five leading compounds (1–5) have pharmacological prospects