Protective Effects of Caffeine on Chikungunya and Zika Virus Infections: An in Vitro and in Silico Study.

Infection by viruses Chikungunya (CHIKV) and Zika (ZIKV) continue to be serious problems in tropical and subtropical areas of the world. Here, we evaluated the antiviral and virucidal activity of caffeine against CHIKV and ZIKV in Vero, A549, and Huh-7 cell lines. Results showed that caffeine displays antiviral properties against both viruses. By pre-and post-infection treatment, caffeine significantly inhibited CHIKV and ZIKV replication in a dose-dependent manner. Furthermore, caffeine showed a virucidal effect against ZIKV. Molecular docking suggests the possible binding of caffeine with envelope protein and RNA-dependent RNA polymerase of CHIKV and ZIKV. This is the first study that showed an antiviral effect of caffeine against CHIKV and ZIKV. Although further studies are needed to better understand the mechanism of caffeine-mediated repression of viral replication, caffeine appears to be a promising compound that could be used for in vivo studies, perhaps in synergy with other compounds present in daily beverages.

Inactivation mechanisms of human adenovirus by e-beam irradiation in water environments.

This study aims to study the kinetics and mechanisms of human adenovirus inactivation by electron beam. Human adenovirus type 5 (HAdV-5) was inoculated in two types of aqueous substrates (phosphate-buffered saline - PBS, domestic wastewater - WW) treated by electron beam at a dose range between 3 and 21 kGy. Samples were evaluated for virus infectivity, PCR amplification of fragments of HAdV-5 genome and abundance and antigenicity of the virion structural proteins. The maximum reduction in viral titre, in plaque-forming units (PFU) per millilitre, was about 7 and 5 log PFU/mL for e-beam irradiation at 20 kGy in PBS and 19 kGy in wastewater, respectively. Among the virion structural proteins detected, the hexon protein showed the higher radioresistance. Long (10.1 kbp) genomic DNA fragments were differently PCR amplified, denoting a substrate effect on HAdV-5 genome degradation by e-beam. The differences observed between the two substrates can be explained by the protective effect that the organic matter present in the substrate may have on viral irradiation. According to the obtained results, the decrease in viral viability/infectivity may be due to DNA damage and to protein alterations. In summary, electron beam irradiation at a dose of 13 kGy is capable of reducing HAdV-5 viral titres by more than 99.99% (4 log PFU/mL) in both substrates assayed, indicating that this type of technology is effective for viral wastewater disinfection and may be used as a tertiary treatment in water treatment plants. KEY POINTS: • The substrate in which the virus is suspended has an impact on its sensitivity to e-beam treatment. • E-beam irradiation at 13 kGy is capable of reducing by 4 Log PFU/mL the HAdV-5 viral titre. • The decrease in viral viability/infectivity may be due to DNA damage and to protein alterations.

Antiviral Effect of Isoquercitrin against Influenza A Viral Infection via Modulating Hemagglutinin and Neuraminidase.

Isoquercitrin (IQC) is a component abundantly present in many plants and is known to have an anti-viral effect against various viruses. In this study, we demonstrate that IQC exhibits strong anti-influenza A virus infection, and its effect is closely related to the suppression of hemagglutinin (HA) and neuraminidase (NA) activities. We used green fluorescent protein-tagged Influenza A/PR/8/34 (H1N1), A/PR/8/34 (H1N1), and HBPV-VR-32 (H3N2) to evaluate the anti-IAV effect of IQC. The fluorescence microscopy and fluorescence-activated cell sorting analysis showed that IQC significantly decreases the levels of GFP expressed by IAV infection, dose-dependently. Consistent with that, IQC inhibited cytopathic effects by H1N1 or H3N2 IAV infection. Immunofluorescence analysis confirmed that IQC represses the IAV protein expression. Time-of-addition assay showed that IQC inhibits viral attachment and entry and exerts a strong virucidal effect during IAV infection. Hemagglutination assay confirmed that IQC affects IAV HA. Further, IQC potently reduced the NA activities of H1N1 and H3N2 IAV. Collectively, IQC prevents IAV infection at multi-stages via virucidal effects, inhibiting attachment, entry and viral release. Our results indicate that IQC could be developed as a potent antiviral drug to protect against influenza viral infection.

Synthesis of New Modified with Rhodamine B Peptides for Antiviral Protection of Textile Materials.

Here we report on the synthesis and characterization of three new N-modified analogues of hemorphin-4 with rhodamine B. Modified with chloroacetyl, chloride cotton fabric has been dyed and color coordinates of the obtained textile materials were determined. Antiviral and virucidal activities of both the peptide-rhodamine B compounds and the dyed textile material were studied. Basic physicochemical properties (acid-base behavior, solvent influence, kinetics) related to the elucidation of structural activity of the new modified peptides based on their steric open/closed ring effect were studied. The obtained results lead to the conclusion that in protic solvent with change in pH of the environment, direct control over the dyeing of textiles can be achieved. Both the new hybrid peptide compounds and the modification of functionalized textile materials with these bioactive hemorphins showed virucidal activity against the human respiratory syncytial virus (HRSV-S2) and human adenovirus serotype 5 (HAdV-5) for different time intervals (30 and 60 min) and the most active compound was Rh-3.

Antiviral activity of Carbenoxolone disodium against dengue virus infection.

As one of the most important mosquito-borne viral diseases, dengue infection is now becoming a global concern due to its rapid spread and rise in incidence. Currently, there is no approved vaccine or effective antiviral drug for dengue virus (DENV) infection. Glycyrrhetinic acid (GNa) and its related derivatives have been reported to inhibit a broad spectrum of viruses. However, it is unknown whether Carbenoxolone disodium (CBX), one of the GNa derivatives, affects DENV infection. Here, we found that the production of infectious DENV particles was significantly decreased by CBX treatment in DENV-permissive cells, while the viral RNA and viral protein synthesis were not affected. Moreover, results from time-of-addition study showed that the inhibitory effect of CBX on DENV was exhibited by targeting the virus itself, not the host cells. Directly incubating DENV with CBX resulted in a remarkable reduction of virus titer and virus infectivity. Furthermore, DENV RNA from progeny virions in the supernatants was significantly decreased by CBX treatment in a dose-dependent manner. Taken together, these data indicate that the antiviral activity of CBX against DENV may be mainly due to a virucidal effect exerted by the compound itself. Our work, for the first time, demonstrates that CBX has antiviral activity against DENV infection, providing useful information for development of potential therapeutic interventions against dengue. J. Med. Virol. 89:571-581, 2017. © 2016 Wiley Periodicals, Inc.

Protective hybrid coating containing silver, copper and zinc cations effective against human immunodeficiency virus and other enveloped viruses.

BACKGROUND: Healthcare-acquired infections by pathogenic microorganisms including viruses represent significant health concern worldwide. Next to direct transmission from person-to-person also indirect transmission from contaminated surfaces is well documented and important route of infections. Here, we tested antiviral properties of hybrid coating containing silver, copper and zinc cations that was previously shown to be effective against pathogenic bacteria including methicillin-resistant Staphylococcus aureus. Hybrid coatings containing silver, copper and zinc cations were prepared through radical polymerization via sol-gel method and applied on glass slides or into the wells of polymethylmethacrylate plates. A 10 µl droplet of several viruses such as human immunodeficiency virus type 1 (HIV-1), influenza, dengue virus, herpes simplex virus, and coxsackievirus was added to coated and uncoated slides or plates, incubated usually from 5 to 240 min and followed by titer determination of recovered virus. RESULTS: Scanning electron microscopy analysis showed better adhesion of coatings on glass surfaces, which resulted in 99.5-100 % HIV-1 titer reduction (3.1 ± 0.8 log10TCID50, n = 3) already after 20 min of exposure to coatings, than on coated polymethylmethacrylate plates with 75-100 % (1.7 ± 1.1 log10TCID50, n = 3) and 98-100 % (2.3 ± 0.5 log10TCID50, n = 3) HIV-1 titer reduction after 20 and 120 min of exposure, respectively. Slower virucidal kinetics was observed with other enveloped viruses, where 240 min exposure to coated slides lead to 97 % (dengue), 100 % (herpes simplex) and 77 % (influenza) reduction in virus titers. Interestingly, only marginal reduction in viral titer after 240 min of exposure was noticed for non-enveloped coxsackie B3 virus. CONCLUSIONS: Our hybrid coatings showed virucidal activity against HIV and other enveloped viruses thus providing further findings towards development of broad-spectrum antimicrobial coating suitable for surfaces in healthcare settings.

The virucidal effects against murine norovirus and feline calicivirus F4 as surrogates for human norovirus by the different additive concentrations of ethanol-based sanitizers.

Since human norovirus is non-cultivable, murine norovirus and feline calicivirus have been used as surrogates. In this study, the virucidal effects of ethanol-based sanitizers with different concentrations of additives (malic acid/sodium malate, glycerin-fatty acid ester) against murine norovirus and feline calicivirus F4 were examined. The ethanol-based sanitizers at pH 7 showed sufficient virucidal effects, but glycerin-fatty acid ester included in ethanol-based sanitizers at pH 4 or 6 reduced the virucidal effects against murine norovirus. The ethanol-based sanitizers containing malic acid/sodium malate inactivated feline calicivirus F4 in shorter time, but there is no difference between ethanol-based sanitizers with and without glycerin-fatty acid ester. Traditionally, feline calicivirus has been used for long time as a surrogate virus for human norovirus. However, this study suggested that murine norovirus and feline calicivirus F4 had different sensitivity with the additive components of ethanol-based sanitizers. Therefore, using feline calicivirus alone as a surrogate for human norovirus may not be sufficient to evaluate the virucidal effect of sanitizers on food-borne infections caused by human norovirus. Sanitizers having virucidal effects against at least both murine norovirus and feline calicivirus may be more suitable to inactivate human norovirus.

Ayurvedic and Chinese Herbs against Coronaviruses.

COVID-19 is a viral disease that infects the lower airways, causing severe acute respiratory syndrome (SARS) and fatal pneumonia. The ripple effect of the COVID-19 outbreak has created serious problems in the healthcare systems of many countries and had far-reaching consequences for the global economy. Thus, effective control measures should be implemented for this coronavirus infection in the future. The ongoing episode of the SARS-CoV-2 sickness, COVID-19, in China, and the subsequent irregular spread of contamination to different nations, has alarmed the clinical and academic community primarily due to the deadly nature of this disease. Being a newly identified virus in the viral classification and having the highest mutation rate, rapid therapeutics are not readily available for treating this ailment, leading to the widespread of the disease and causing social issues for affected individuals. Evidence of Ayurveda and traditional Chinese medicine (TCM) has been found in ancient civilizations, such as those of the Hindus, Babylonians, Hebrews, and Arabs. Although TCM and Ayurvedic herbs do not promise to be very effective treatments for this pandemic, they can reduce infectivity and virulence by enhancing immunity and showing effectiveness in rehabilitation after COVID-19 disease. Thus, they could be used as sources of inhibitor molecules for certain phenomena, such as viral replication, attachment to the host, 3CL protease inhibition, 3a ion channel inhibitors, and reverse transcription inhibition. Medicinal plants from TCM and Ayurveda and their biologically active phytoconstituents can effectively modulate the targets and pathways relevant to inflammation and immune responses in human bodies. The present review analyzes the role of certain TCM and Ayurvedic medicinal plants in healing COVID-19 infection. Medicinal plants such as Glycyrrhiza glabra (licorice), Curcuma longa (turmeric), and Zingiber officinale (ginger) are regarded as the main antiviral herbs. Their extracts and individual bioactive compounds could be used as potential substances for developing remedies to prevent or cure the coronavirus disease. Generally, antiviral phytochemicals obtained from natural sources are considered potent candidates for fighting COVID-19 infection and rehabilitation after it.

Inhibition of influenza a virus infection by natural stilbene piceatannol targeting virus hemagglutinin.

BACKGROUND: Given the magnitude of influenza pandemics as a threat to the global population, it is crucial to have as many prevention and treatment options as possible. Piceatannol (PIC) is a tetrahydroxylated stilbenoid (trans-3,4,3',5'-tetrahydroxystilbene), also known as 3'- hydroxy resveratrol, which has demonstrated many different biological activities such as anti-inflammatory and antiviral activities. PURPOSE: In this study, the anti-influenza A virus (IAV) activities and mechanisms of PIC in vitro and in vivo were investigated in order to provide reference for the development of novel plant-derived anti-IAV drugs. METHODS: The viral plaque assay, RT-PCR and western blot assay were used to evaluate the anti-IAV effects of PIC in vitro. The anti-IAV mechanism of PIC was determined by HA syncytium assay, DARTS assay and Surface Plasmon Resonance assay. The mouse pneumonia model combined with HE staining were used to study the anti-IAV effects of PIC in vivo. RESULTS: PIC shows inhibition on the multiplication of both H1N1 and H3N2 viruses, and blocks the infection of H5N1 pseudovirus with low toxicity. PIC may directly act on the envelope of IAV to induce the rupture and inactivation of IAV particles. PIC can also block membrane fusion via binding to HA2 rather than HA1 and cleavage site of HA0. PIC may interact with the two residues (HA2-T68 and HA2-I75) of HA2 to block the conformational change of HA so as to inhibit membrane fusion. Importantly, oral therapy of PIC also markedly improved survival and reduced viral titers in IAV-infected mice. CONCLUSION: PIC possesses significant anti-IAV effects both in vitro and in vivo and may block IAV infection mainly through interaction with HA to block membrane fusion. Thus, PIC has the potential to be developed into a new broad-spectrum anti-influenza drug for the prevention and treatment of influenza.

Virucidal Activity of the Pyridobenzothiazolone Derivative HeE1-17Y against Enveloped RNA Viruses.

Pyridobenzothiazolone derivatives are a promising class of broad-spectrum antivirals. However, the mode of action of these compounds remains poorly understood. The HeE1-17Y derivative has already been shown to be a potent compound against a variety of flaviviruses of global relevance. In this work, the mode of action of HeE1-17Y has been studied for West Nile virus taking advantage of reporter replication particles (RRPs). Viral infectivity was drastically reduced by incubating the compound with the virus before infection, thus suggesting a direct interaction with the viral particles. Indeed, RRPs incubated with the inhibitor appeared to be severely compromised in electron microscopy analysis. HeE1-17Y is active against other enveloped viruses, including SARS-CoV-2, but not against two non-enveloped viruses, suggesting a virucidal mechanism that involves the alteration of the viral membrane.

Inactivation of SARS-CoV-2 by Commercially Available Disinfectants and Cleaners.

The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major burden for health care systems worldwide, and is a threat to our daily lives. Various effective ingredients against SARS-CoV-2 were already reported, however, since products contain various ingredients, it is also important to evaluate the effectiveness of commercially available disinfectants per se. In this study, the virucidal efficacy of forty-eight commercially available products were evaluated according to the standardized suspension method EN 14476 and the following results were obtained: Alcohol-based disinfectants, hand soaps, wet wipes, alkaline cleaners, quaternary ammonium compound sanitizers and oxygen bleach had great virucidal efficacy against SARS-CoV-2. Enveloped viruses such as SARS-CoV-2 are among the most susceptible of pathogens to formulated microbicidal actives and detergents, but as the results of this study showed, it is also necessary to pay attention to the concentration at the time of use and the required contact time.

Antiviral activity of Epimedium koreanum Nakai water extract against influenza viruses.

Epimedium koreanum Nakai (EKN) is a popular plant in Korean and Chinese medicine for treating a variety of ailments. The aqueous extract of EKN has a significant inhibitory impact on influenza A virus (IAV) infection by directly blocking viral attachment and having a virucidal effect, according to this study. Using fluorescent microscopy and fluorescence-activated cell sorting (FACS) with a green fluorescent protein (GFP)-tagged Influenza A/PR/8/34 virus, we examined the effect of EKN on viral infection. By viral infection, EKN strongly suppresses GFP expression, and at a dosage of 100 µg/mL, EKN decreased GFP expression by up to 90% of the untreated infected control. Immunofluorescence and Western blot analyses against influenza viral proteins revealed that EKN decreased influenza viral protein expression in a dose-dependent manner. EKN inhibited the H1N1 influenza virus's hemagglutinin (HA) and neuraminidase (NA), preventing viral attachment to cells. Furthermore, EKN had a virucidal impact and inhibited the cytopathic effects of H1N1, H3N2 and influenza B virus infection. Finally, our findings show that EKN has the potential to be developed as a natural viral inhibitor against influenza virus infection.

Broccoli Leaves Attenuate Influenza A Virus Infection by Interfering With Hemagglutinin and Inhibiting Viral Attachment.

Broccoli (Brassica oleracea L. var. Italica) leaves are a byproduct of broccoli and could be used as a food source. The study aimed to evaluate the effect of broccoli leaves on influenza A virus (IAV) infection. We investigated the effect of ethanol extract of Broccoli leaves (EBL) on IAV infection using green fluorescent protein (GFP)-tagged Influenza A/PR/8/34 virus (PR8-GFP IAV). When EBL and PR8-GFP IAV were cotreated to RAW 264.7 cells, the fluorescence microscopy and fluorescence-activated cell sorting (FACS) analysis showed that EBL significantly reduced the levels of GFP expression by influenza viral infection dose-dependently. Immunofluorescence (IF) analysis confirmed that EBL decreased the expression of IAV proteins. EBL exhibited a strong inhibitory effect of IAV binding on the cells and moderate virucidal impact. Consistently, EBL potently suppressed the hemagglutination by IAV infection. These results indicate that EBL prevents IAV attachment via the inhibition of HA upon viral infection. Finally, EBL as an HA inhibitor of IAV could be used as the natural antiviral source to protect against influenza viral infection.

Synthesis of water-soluble porphyrin with tyrosine fragments and study of its interaction with S-protein of SARS-CoV-2.

The multistage purposeful synthesis of 5,15-bis(4'-l-N-tyrosinylamidophenyl)-10,20-bis(N-methylpyridin-3'-yl)porphine diiodide was carried out, and the optimum synthesis conditions were determined. 5,15-Bis(4'-nitrophenyl)-10,20-bis(pyridin-3'-yl)porphine served as the starting porphyrin. The structure, individual character, and purity of the target compound were proved by electron spectroscopy, 1H NMR spectroscopy, mass spectrometry (MALDI TOF), and TLC. Specific features of the interaction of the synthesized porphyrin with S-protein of SARS-CoV-2 were studied using spectral and thermochemical methods, including conditions of photoirradiation. The photoirradiation of the synthesized porphyrin in a complex with the SARS-CoV-2 S-protein can result in the partial oxidation of amino acid residues of the protein and distort its primary and secondary structures. The photoirradiation of the S-protein complex with the porphyrin decreases its thermal resistance to melting by 15 °C compared to the free S-protein and causes porphyrin release.

[Do liquid wastes from automated instruments in medical laboratories have their proper microbicide effect?] / Les rejets liquides des automates de biologie médicale ont-ils un effet microbicide propre qui permettrait de s'affranchir de leur traitement pour risque infectieux ?

Liquid wastes from clinical biology automated systems are currently evacuated in the urban network after chemical treatment to eliminate a possible risk of infection. Since these wastes are ecotoxic because of the presence of numerous chemical reagents, we studied their intrinsic microbicidal power towards a selection of infectious agents widely found in clinical specimens. The objective was to determine if an additional anti-infectious treatment before elimination is necessary. Thus, we evaluated the bactericidal effect of liquid wastes of several automated systems towards four bacterial species (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis) and their virucidal activity against a non-enveloped virus, resistant in the environment (adenovirus). This effect was determined for different exposure times. Our results showed that the antibacterial activity was highly variable depending on the waste-bacteria pair considered (varying from no activity to complete sterilization of a strong bacterial inoculum). The liquid wastes were on the other hand globally inactive towards adenovirus.

Inhibitory effects of bee venom and its components against viruses in vitro and in vivo.

Bee venom (BV) from honey bee (Apis Melifera L.) contains at least 18 pharmacologically active components including melittin (MLT), phospholipase A2 (PLA2), and apamin etc. BV is safe for human treatments dose dependently and proven to possess different healing properties including antibacterial and antiparasitidal properties. Nevertheless, antiviral properties of BV have not well investigated. Hence, we identified the potential antiviral properties of BV and its component against a broad panel of viruses. Co-incubation of non-cytotoxic amounts of BV and MLT, the main component of BV, significantly inhibited the replication of enveloped viruses such as Influenza A virus (PR8), Vesicular Stomatitis Virus (VSV), Respiratory Syncytial Virus (RSV), and Herpes Simplex Virus (HSV). Additionally, BV and MLT also inhibited the replication of non-enveloped viruses such as Enterovirus-71 (EV-71) and Coxsackie Virus (H3). Such antiviral properties were mainly explained by virucidal mechanism. Moreover, MLT protected mice which were challenged with lethal doses of pathogenic influenza A H1N1 viruses. Therefore, these results provides the evidence that BV and MLT could be a potential source as a promising antiviral agent, especially to develop as a broad spectrum antiviral agent.

Evaluation of the inactivation of human Coxsackievirus by thermophilic and mesophilic anaerobic digestion using integrated cell culture and reverse transcription real-time quantitative PCR.

The virucidal effects of anaerobic digestion were evaluated using human Coxsackievirus as a model for the Enterovirus family. Coxsackievirus was inactivated completely by thermophilic anaerobic digestion (TAD). By 4 h no living and infectious virus remained and no detectable viral RNA was present after 2 days in TAD (7.0 log reduction). Compared to TAD, 2.6 log reduction of viral RNA was achieved by 14 days in mesophilic anaerobic digestion (MAD) (p < 0.0001). Although cytopathogenic effect was not observed in the cultured cells, low levels of intracellular viral RNA were detected after one day of MAD treatment indicating that Coxsackievirus had infected the cells but could not replicate. The combination of thermal and biochemical effects in TAD plays a critical role for viral disinfection. The results of this study indicate that selection of the right configuration of anaerobic digestion for treatment of biowaste may reduce the risk of viral contamination to the environment and water source.