Virucidal Effect Research Articles

Virucidal Effects of Bleach Activators, Sodium Alkyl Acyloxybenzene Sulfonate and Acyloxybenzoic Acid, Against Feline calicivirus

Noroviruses (NVs) are major causative pathogens of gastroenteritis. The disinfection of contaminated clothing during common household washing is desirable. The virucidal effects of 2 bleach activators, sodium alkyl acyloxybenzene sulfonate (OBS) and alkyl acyloxybenzoic acid (OBC), were studied using Feline calicivirus (FCV) as a surrogate for NVs. FCV was added to solutions containing either OBS or OBC and sodium percarbonate at various temperatures and for varying lengths of time. OBS and OBC, which generate long carbon chain peroxy acids, enhanced the virucidal effect of sodium percarbonate (PC). In particular, sodium lauroyloxybenzene sulfonate (OBS-12) and decanoyloxybenzoic acid (OBC-10) showed superior virucidal effects. Although the virucidal effect of 38-200 mg/L OBS-12 was maintained with 2-5% (v/v) horse serum, there was less of an effect with the same concentration of available chlorine. OBS and OBC have been used as ingredients in some laundry products to increase bleaching activity. It is expected that the use of OBS and OBC is also effective for the inactivation of NVs under common household washing conditions.

Bilirubin: An Endogenous Molecule with Antiviral Activity in vitro

Bilirubin-IX-alpha (BR) is the final product of heme metabolism through the heme oxygenase/biliverdin reductase (HO/BVR) system. Previous papers reported on the microbicidal effects of the HO by-products biliverdin-IX-alpha, carbon monoxide and iron, through either direct or indirect mechanisms. In this paper the evidence of a virucidal effect of BR against human herpes simplex virus type 1 (HSV-1) and the enterovirus EV71 was provided. Bilirubin-IX-alpha, at concentrations 1–10 μM, close to those found in blood and tissues, significantly reduced HSV-1 and EV71 replication in Hep-2 and Vero cell lines, respectively. Bilirubin-IX-alpha inhibited viral infection of Hep-2 and Vero cells when given 2 h before, concomitantly and 2 h after viral infection. Furthermore, BR retained its antiviral activity even complexed with a saturating concentration of human serum-albumin. Moreover, 10 μM BR increased the formation of nitric oxide and the phosphorylation of c-Jun N-terminal kinase in Vero and Hep-2 cell lines, respectively, thus implying a role of these two pathways in the mechanism of antiviral activity of the bile pigment. In conclusion, these results support the antiviral effect of BR against HSV-1 and enterovirus in vitro, and put the basis for further basic and clinical studies to understand the real role of BR as an endogenous antiviral molecule.

Virucidal efficacy of hydrogen peroxide vapour disinfection

Viral contamination of surfaces is thought to be important in transmission. Chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (HPV) against enteric and respiratory viruses. To measure the virucidal efficacy of HPV against respiratory and enteric viruses on materials representing those found in institutions and homes. Poliovirus, human norovirus genogroup II.4 (GII.4), murine norovirus 1, rotavirus, adenovirus and influenza A (H1N1) virus dried on to stainless steel, framing panel and gauze carriers were exposed to HPV 127 ppm for 1h at room temperature in an isolator. Poliovirus was also exposed to HPV at different locations in a room. The virucidal effect was measured by comparing recoverable viral titres against unexposed controls. Polymerase chain reaction was used to evaluate the effect of HPV on viral genome reduction. HPV disinfection resulted in complete inactivation of all viruses tested, characterized by >4 log(10) reduction in infectious particles for poliovirus, rotavirus, adenovirus and murine norovirus on stainless steel and framing panel carriers, and >2 log(10) reduction for influenza A virus on stainless steel and framing panel carriers, and for all viruses on gauze carriers. Complete inactivation of poliovirus was demonstrated at several locations in the room. Reductions in viral genomes were minimal on framing panel and gauze carriers but significant on stainless steel carriers; human norovirus GII.4 genome was most resistant to HPV treatment. HPV could be an effective virucidal against enteric and respiratory viruses contaminating in-house environments.

Abalone herpes virus stability in sea water and susceptibility to chemical disinfectants

Experimental infection models using immersion and injection challenges were developed to investigate the effects of various physicochemical treatments on the abalone herpes virus (AbHV), an emerging virus causing viral ganglioneuritis in abalone in Australia. To determine stability at different temperatures, the virus was held at 4, 15, or 25 °C for 1, 5, and 12 days prior to immersion challenge of naïve abalone. Mortality curves indicated that when held for 1 day in sea water at 4 °C and 15 °C the virus remained infectious and highly pathogenic. In addition, the virus retained partial infectivity after 5 days held at 4 °C. Histological examination of abalone tissues following viral exposure confirmed the presence of lesions typical of abalone viral ganglioneuritis in animals showing morbidity signs. An additional experiment was performed to determine the virucidal efficacy of three disinfectants (calcium hypochlorite, Buffodine and the non-ionic surfactant Impress). The disinfectants were used at various doses and durations to treat AbHV prior to injection and immersion challenges. Results showed that Buffodine and the non-ionic surfactant Impress were effective at inactivating the virus with no detectable adverse effects on the abalone's health. In addition, calcium hypochlorite showed a virucidal effect when used on lower titres of virus prior to immersion challenge.

A respiratory syncytial virus isolate enables the testing of virucidal products

The respiratory syncytial virus (RSV) is known as a major cause of respiratory infections and nosocomial diseases. Testing this virus is rather difficult due to the problems encountered in producing it at a high titer without using any purification method. A RSV isolate which replicates to high level on a Hep-2 cell line with an infectious titer of at least 10(7)TCID(50)mL(-1) in culture supernatant fluids has been identified. Thanks to this isolate, the virucidal effects of two products, a hand rub solution and a surface disinfectant, were conveniently tested according to the EN 14476:2007-02 procedure.

Inhibitory effect of aromatic herbs, lavender, sage and chamomile against herpes simplex virus infection

This study demonstrated anti-herpes simplex virus (HSV) activity of lavender, sage and chamomile extracts. Green monkey kidney cells were protected from HSV-2 infection by dichloromethane and methanol extract of lavender with therapeutic indices (TI) of 1.98 and 2.90, respectively when the cells were treated before viral infection. Moreover, the dichloromethane extract of chamomile showed the highest TI which was 20.74 against HSV-1 when the virus was treated during adsorption. The inhibitory effect of dichloromethane extract of lavender significantly had the highest TI (45.90) when HSV-1 was treated after viral adsorption. The highest inhibitory effect against HSV-2 was observed after treatment of the virus with methanol and dichloromethane extracts of sage, with TIs of 9.02 and 10.1, respectively. Chamomile extracts showed significant virucidal effects on both HSV-1 and HSV-2 viral particles. The inhibitory effect of chamomile extracts on HSV-1 and HSV-2 viral yield after viral replication was the highest at 30 h after treatment. Respective reductions of viral titers by 9.7 and 7.1 fold were observed when cells were treated with dichloromethane and methanol extract of chamomile. Therefore, chamomile, sage and lavender were demonstrated to possess anti-herpes simplex virus activities at various stages of the viral multiplication cycle. Key words : Chamomile, sage, lavender, herpes simplex virus (HSV), anti-herpes simplex virus.

Antiviral mode of action of bovine dialyzable leukocyte extract against human immunodeficiency virus type 1 infection

BackgroundBovine dialyzable leukocyte extract (bDLE) is derived from immune leukocytes obtained from bovine spleen. DLE has demonstrated to reduce transcription of Human Immunodeficiency Virus Type 1 (HIV-1) and inactivate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Therefore, we decided to clarify the mode of antiviral action of bDLE on the inhibition of HIV-1 infection through a panel of antiviral assays.ResultsThe cytotoxicity, HIV-1 inhibition activity, residual infectivity of bDLE in HIV-1, time of addition experiments, fusion inhibition of bDLE for fusogenic cells and the duration of cell protection even after the removal of bDLE were all assessed in order to discover more about the mode of the antiviral action.HIV-1 infectivity was inhibited by bDLE at doses that were not cytotoxic for HeLa-CD4-LTR-β-gal cells. Pretreatment of HIV-1 with bDLE did not decrease the infectivity of these viral particles. Cell-based fusion assays helped to determine if bDLE could inhibit fusion of Env cells against CD4 cells by membrane fusion and this cell-based fusion was inhibited only when CD4 cells were treated with bDLE. Infection was inhibited in 80% compared with the positive (without EDL) at all viral life cycle stages in the time of addition experiments when bDLE was added at different time points. Finally, a cell-protection assay against HIV-1 infection by bDLE was performed after treating host cells with bDLE for 30 minutes and then removing them from treatment. From 0 to 7 hours after the bDLE was completely removed from the extracellular compartment, HIV-1 was then added to the host cells. The bDLE was found to protect the cells from HIV-1 infection, an effect that was retained for several hours.ConclusionsbDLE acted as an antiviral compound and prevented host cell infection by HIV-1 at all viral life cycle stages. These cell protection effects lingered for hours after the bDLE was removed. Interestingly, bDLE inhibited fusion of fusogenic cells by acting only on CD4 cells. bDLE had no virucidal effect, but could retain its antiviral effect on target cells after it was removed from the extracellular compartment, protecting the cells from infection for hours.bDLE, which has no reported side effects or toxicity in clinical trials, should therefore be further studied to determine its potential use as a therapeutic agent in HIV-1 infection therapy, in combination with known antiretrovirals.

Antiviral Activity of Inonotus Obliquus Fungus Extract towards Infection Caused by Hepatitis C Virus in Cell Cultures

Fractions of Inonotus obliquus fungus water extract exhibited a virucidal effect towards hepatitis C virus: it 100-fold reduced its infective properties within 10 min. The antiviral effects of fungus extracts manifested after preventive (24 h before infection) and therapeutic use (during infection of porcine embryo kidney cells). Moreover, the data indicate that the birch fungus extracts inhibit production of infective virus by porcine embryo kidney cells.

Antiviral effects of blackberry extract against herpes simplex virus type 1

The aim of this study was to evaluate antiviral properties of blackberry extract against herpes simplex virus type 1 (HSV-1) in vitro. HSV-infected oral epithelial (OKF6) cells and cell-free virus suspensions were treated with blackberry extract (2.24-1,400 μg/mL), and virus yield and infectivity were quantified by direct plaque assay. Blackberry extract ≥56 μg/mL inhibited HSV-1 replication in oral epithelial cells by >99% (P < .005). Concentrations ≥280 μg/mL were antiviral when the extract was added after virus adsorption and entry. Exposure of cell-free virus to ≥280 μg/mL blackberry extract for 15 minutes at room temperature was virucidal (P = .0002). The virucidal effects were not due to pH changes at concentrations up to 1,500 μg/mL. Blackberry extract inhibited the early stages of HSV-1 replication and had potent virucidal activity. These properties suggest that this natural fruit extract could provide advantage as a topical prophylactic/therapeutic agent for HSV infections.

Bioactivity of in vitro glycoalkaloids from Solanum nigrum

Glycoalkaloids were produced from callus and regenerated plants of Solanum nigrum L. (Solanaceae) using different concentrations of auxins and cytokinins.The glycoalkaloids were separated by acid base precipitation, and determined by high performance liquid chromatography. The produced glycoalkaloids found to have antioxidant activity against the free radical DPPH. Also, they exhibited cytotoxic activity against the selected carcinoma cell lines including liver, breast and lymphoplastic leukemia cell lines. Examination of the antiviral activity showed that glycoalkaloids had virucidal effect against the tested virus strains. In addition, callus glycoalkaloids were found to have antischistomiasis and antifasciolos activities.

Antiherpetic activity of a sulfated polysaccharide from Agaricus brasiliensis mycelia

Sulfated polysaccharides are good candidates for drug discovery in the treatment of herpetic infections. Agaricus brasiliensis (syn A. subrufescens, A. blazei) is a Basidiomycete fungus native to the Atlantic forest region of Southeastern Brazil. Herein we report the chemical modification of a polysaccharide extracted from A. brasiliensis mycelia to obtain its sulfated derivative (MI-S), which presented a promising inhibitory activity against HSV-1 [KOS and 29R (acyclovir-resistant) strains] and HSV-2 strain 333, with selectivity indices (SI=CC50/IC50) higher than 439, 208, and 562, respectively. The mechanisms underlying this inhibitory activity were scrutinized by plaque assay with different methodological strategies. MI-S had no virucidal effects, but inhibited HSV-1 and HSV-2 attachment, penetration, and cell-to-cell spread, as well as reducing the expression of HSV-1 ICP27, UL42, gB, and gD proteins. MI-S also presented synergistic antiviral effect with acyclovir. These results suggest that MI-S presents multiple modes of anti-HSV action.

Antiviral Activities of Sulfated Polysaccharides Isolated from Sphaerococcus coronopifolius (Rhodophytha, Gigartinales) and Boergeseniella thuyoides (Rhodophyta, Ceramiales)

Water-soluble sulfated polysaccharides isolated from two red algae Sphaerococcus coronopifolius (Gigartinales, Sphaerococcaceae) and Boergeseniella thuyoides (Ceramiales, Rhodomelaceae) collected on the coast of Morocco inhibited in vitro replication of the Human Immunodeficiency Virus (HIV) at 12.5 μg/mL. In addition, polysaccharides were capable of inhibiting the in vitro replication of Herpes simplex virus type 1 (HSV-1) on Vero cells values of EC50 of 4.1 and 17.2 μg/mL, respectively. The adsorption step of HSV-1 to the host cell seems to be the specific target for polysaccharide action. While for HIV-1, these results suggest a direct inhibitory effect on HIV-1 replication by controlling the appearance of the new generations of virus and potential virucidal effect. The polysaccharides from S. coronopifolius (PSC) and B. thuyoides (PBT) were composed of galactose, 3,6-anhydrogalactose, uronics acids, sulfate in ratios of 33.1, 11.0, 7.7 and 24.0% (w/w) and 25.4, 16.0, 3.2, 7.6% (w/w), respectively.

Inhibitory effects of tricin derivative from Sasa albo-marginata on replication of human cytomegalovirus

The anti-human cytomegalovirus (HCMV) activity of tricin (4′,5,7-trihydroxy-3′,5′-dimethoxyflavone), a derivative from Sasa albo-marginata, was studied in the human embryonic fibroblast cell line MRC-5. In a plaque assay, tricin and ganciclovir (GCV) showed concentration-dependent inhibitory properties from 0.05 to 3.6 μM and 0.01 to 1.0 μM, respectively. Tricin had no virucidal effects on cell-free HCMV. Treatment with tricin 1 h before, or 1 h or 3 h after viral infection significantly suppressed HCMV replication. Moreover, tricin inhibited the expression of immediate early (IE) 2 mRNA and DNA polymerase (UL54) mRNA in HCMV-infected cells. Western blot analysis also demonstrated that tricin decreased the expression of IE antigen (especially IE2) and cyclooxygenase 2 (COX-2) expression in HCMV-infected cells. In the presence of tricin, prostaglandin E2 (PGE 2) accumulation by HCMV infection was completely inhibited. These results suggest that tricin is a novel compound with potential COX inhibitor-dependent anti-HCMV activity.

Inhibition of multiplication of herpes simplex virus by caffeic acid

Hot water extracts of coffee grinds and commercial instant coffee solutions have been shown to exhibit marked antiviral and virucidal activities against herpes simplex virus type 1 (HSV-1). Specifically, it has been shown that caffeine and N-methyl-pyridinium formate inhibit the multiplication of HSV-1 in HEp-2 cells. The present study examined the virological properties and the antiviral activity of caffeic acid against HSV-1. Caffeic acid inhibited the multiplication of HSV-1 in vitro, while chlorogenic acid, a caffeic acid ester with quinic acid, did not. These reagents did not have a direct virucidal effect. The one-step growth curve of HSV-1 showed that the addition of caffeic acid at 8 h post infection (h p.i.) did not significantly affect the formation of progeny viruses. An analysis of the influence of the time of caffeic acid addition, revealed that addition at an early time post infection remarkably inhibited the formation of progeny infectious virus in the infected cells, but its addition after 6 h p.i. (i.e., the time of the completion of viral genome replication) did not efficiently inhibit this process. These results indicate that caffeic acid inhibits HSV-1 multiplication mainly before the completion of viral DNA replication, but not thereafter. Although caffeic acid showed some cytotoxicity by prolonged incubation, the observed antiviral activity is likely not the secondary result of the cytotoxic effect of the reagent, because the inhibition of the virus multiplication was observed before appearance of the notable cytotoxicity.

LTB4 increases nasal neutrophil activity and conditions neutrophils to exert antiviral effects

BackgroundLeukotriene B4 (LTB4) recruits and activates neutrophils. Accordingly, this leukotriene is involved in innate defense actions.ObjectiveTo examine if nasal LTB4 can produce neutrophil activity and to explore whether or not LTB4 can condition neutrophils to exert virucidal effects in vitro and in vivo.Methods1. Twenty-three healthy subjects received nasal LTB4 in a randomized and sham-controlled design. Symptoms were scored and nasal lavages carried out. Myeloperoxidase (MPO) and α-defensins were monitored as indices of neutrophil activity. IL-8, eosinophil cationic protein (ECP) and α2-macroglobulin were measured as indices of pro-inflammatory cytokine production, eosinophil activity, and plasma exudation. 2. Supernatants from neutrophils activated by LTB4 in vitro were assayed for virucidal activity against respiratory viruses. 3. In 38 healthy individuals, nasal inoculation with human rhinovirus-16 (HRV-16) was performed. In a preliminary study, intervention with LTB4 was given in a randomized and controlled design. Symptoms, virus replication, and antibody-titres were monitored.Results1. LTB4 produced statistically significant increases in MPO and α-defensins, whereas IL-8, ECP, and α2-macroglobulin were unaffected. 2. The supernatants efficiently killed human coronavirus, respiratory syncytial virus, and influenza B virus. 3. HRV-16 replication was lower in subjects receiving LTB4, but this difference failed to reach statistical significance. Common cold symptoms and incidence of seroconversion were unaffected.ConclusionNasal LTB4 induces a selective recruitment/activation of neutrophils. LTB4 can condition neutrophils to exert virucidal effects in vitro and may reduce virus replication in vivo. We suggest that the condition induced by LTB4 reflects an enhanced state of innate defense.

Antiviral and Virucidal Activities of N-Cocoyl-L-Arginine Ethyl Ester

Various amino acid-derived compounds, for example, Nα-Cocoyl-L-arginine ethyl ester (CAE), alkyloxyhydroxylpropylarginine, arginine cocoate, and cocoyl glycine potassium salt (Amilite), were examined for their virucidal activities against herpes simplex virus type 1 and 2 (HSV-1 and HSV-2), influenza A virus (IAV), and poliovirus type 1 (PV-1) in comparison to benzalkonium chloride (BKC) and sodium dodecylsulfate (SDS) as a cationic and anionic control detergent and also to other commercially available disinfectants. While these amino acid-derived compounds were all effective against HSV-1 and HSV-2, CAE and Amilite were the most effective. These two compounds were, however, not as effective against IAV, another enveloped virus, as against HSV. Cytotoxicity of CAE was weak; at 0.012%, only 5% of the cells were killed under the conditions, in which 100% cells were killed by either SDS or BKC. In addition to these direct virucidal effects, CAE inhibited the virus growth in the HSV-1- or PV-1-infected cells even at 0.01%. These results suggest a potential application of CAE as a therapeutic or preventive medicine against HSV superficial infection at body surface.

MECHANISMS OF ANTIVIRAL ACTION OF SEEDS FROM Guettarda angelica Mart. AGAINST BOVINE AND SWINE HERPESVIRUSES IN VITRO

Crude aqueous extract from seeds (AEs) of Guettarda angelica Mart. (Rubiaceae) presented in vitro antiviral activity against bovine (BoHV-1) and swine (SuHV-1) herpesviruses type 1 in our previous studies. The aim of the current work was to continue the studies with this extract in order to determine its mode of antiviral action on these two animal herpesviruses. For this, at non cytotoxic concentration (40 µg/mL), the AEs extract was added at different times to the cells or viruses during infection. The antiviral tests were performed using the viral titer reduction assay and expressed in inhibition percentage (IP). The mechanism studies showed that AEs blocked BoHV-1 binding to MDBK cells in 99%; inhibited both during and after virus adsorption by more than 97% for both viruses. Moreover, AEs inactivated both viruses extracellular and directly by 99%. These results indicate that AEs has a broad spectrum of action since it was able either to exert a direct virucidal effect or to present an antiviral activity before and after the attachment phase. Seeds of G. angelica might be a promising source of antiviral agents and merits further investigation. DOI: http://dx.doi.org/10.17525/vrr.v15i2.46

Potent virucidal effect of pheophorbide a and pyropheophorbide a on enveloped viruses

In this study, we evaluated the inhibitory effect of ethanol and aqueous extracts from a stem of Opuntia ficus indica on replication of three kinds of viruses: two enveloped viruses [herpes simplex virus type 2 (HSV-2), influenza A virus (IFV-A)], and one non-enveloped virus [poliovirus type 1 (PV-1)]. Only ethanol extract from the cactus stem showed significant antiviral activity in vitro. Two chlorophyll derivatives, pheophorbide a and pyropheophorbide a, were isolated as active substances exhibiting potent virucidal effects on HSV-2 and IFV-A, but no activity against PV-1 was observed. These findings suggest that these active compounds might recognize specific glycoproteins of enveloped viruses, precluding their binding to host cell receptors and inhibiting viral infections.

Anti-adenoviral substances isolated from medicinal plants: current status and future prospects

Development of safe and commonly approved antiviral therapy and/or immunotherapy for infections caused by human double-stranded DNA adenoviruses (HAdVs) in a variety of immunocompromised hosts as AIDS patients, hereditary immunodeficient subjects, pediatric solid organ or haematopoietic steam cell transplant recipients, is still a challenging issue. Thus, the recently reported advances in the development of extraction, identification, cytotoxicity evaluation, proteomic profiling and antiviral activity assays protocols used for search of substances with medicinal plant origin which indicated selective and potent activity against human adenoviruses causing a number of self-limiting mild respiratory, gastrointestinal, genitourinary, ocular and obesity-related [1,2] infectious disease has been reviewed. The performed meta-analysis of these research showed that a still limited set of the plant derived active compounds as some catechins, hydroxyflavones, metoxyflavones, polyphenol acids, depsides, pentacyclic triterpenes, and terpene alcohols has been identified to cause in vitro and in vivo effects on specific human adenovirus inactivation and growth. A significant anti-HAdV activity at non-toxic concentration for some fractions of ethanolic- or water-type extracts obtained from a restrained number of medicinal plants with ethno-medical background and belonging to different plant families have been also described. However, further and more intensified research is needed to elucidate the active constituents of these plants and to establish detailed mechanism of their anti-adenoviral and virucidal effects to enable development of effective and marketable anti-HAdVs agents.

Potent In Vitro Inactivation of Both Free and Cell-Associated CCR5- and CXCR4-Tropic HIV-1 by Common Commercial Soap Bars From South Africa

We showed herein the potent virucidal effect of soap and water solutions against both CCR5-tropic and CXCR4-tropic cell-free HIV-1 strains, and cytotoxicity for HIV-1-infected lymphocytes during short incubation durations, ranging from 30 seconds to 2 minutes. These observations indicate a rapid inhibitory effect of soap and water on viral infectivity.