Antiviral activities of extracts from Hong Kong seaweeds

We extracted six Hong Kong brown seaweed species with hot water for their antiviral properties. The cytotoxicity and antiviral activity of these extracts were tested by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenlytetrezolium bromide] method, cytopathic effect reduction assay, and plaque reduction assay. The antiviral effect was further determined by flow cytometric analysis. The results showed that most of these extracts inhibited the propagation of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) standard strains with very low cytotoxicity to the host cells. The extracts of Hydroclathrus clathratus and Lobophora variegata showed more potential anti-HSV activities than the extracts of the other four seaweeds. They also had moderate anti- respiratory syncytial virus (RSV) activities but could not inhibit influenza A virus. Hydroclathrus clathratus was further extracted by diluted acid and alkali and the antiviral effects of the extracts were also detected. The result showed that the hot water extract contained the main carbohydrate components that exhibited the antiviral activities against various strains of HSV, including the acyclovir-resistant strain. HI-3, a compound fractionated from this hot water extract, showed a dose-dependent anti-HSV activity in flow cytometric analysis and plaque reduction assay.

Toxicity and Antiviral Activities of Some Medicinal Plants Used by Traditional Medical Practitioners in Zimbabwe

Genital herpes, usually caused by Herpes Simplex Virus type-2 (HSV-2), is the commonest sexually transmitted disease especially amongst rural women in Southern Africa including Zimbabwe. This predisposes them to HIV/AIDS infection, cancer and opportunistic infections (OIs). Current antiviral treatments are often cytotoxic and/or ineffective. This motivates active research to find alternative safer drugs or lead drugs from traditional medicinal sources. Twenty six (26) methanol extracts from commonly used and often endangered plant species (14) used by communities and traditional medical practitioners for treating illnesses and sexually transmitted diseases from 5-selected districts of Zimbabwe were investigated for toxicity by Brine shrimp lethality test (BSLT) and by 50% Cytopathic effect on VERO cultured cells. The extracts were also tested for antiviral activity against Herpes Simplex Virus-2 (HSV-2) by the End Point Titration Technique (EPTT) and Neutralisation Test (NT) on VERO cells. Results from the BSLTs ranged 66.66 - 4304 μg/ml;50% Cytopathic effect from 19.53 - 312 μg/ml whilst the NT ID50 values ranged from 10.41 - 125 μg/ml. The antiviral EPTT reduction factor (RF) was 1 - 104 with 13 extracts showing RF ≥ 103. All the plant extracts had moderate to high toxicity (LC50, 789 - 66 μg/ml) in the BSLT. Six extracts had LC50 values greater than 1000 μg/ml. All 26 extracts were cytotoxic with CC50 values < 500 ug/ml of which 19 were more toxic CC50 in vitro therapeutic indexes ≥ 3.7. Cassia abbreviata, Dichrostachys cinerea and Hypoxis hemerocallidea had therapeutic indexes (TI) 7.5 - 15.0. The more active plant extracts were from roots and root tubers. The results confirm the rationale for the use of traditional medicinal plants by traditional medical practitioners for treating various diseases and could bring awareness for their better use and improve conservation. The results also provide an opportunity to develop more efficacious drugs by isolating lead compounds and determining their mode of action.

Anti-infective immune functions of type Ⅳ interferon in grass carp(Ctenopharyngodon idella):A novel antibacterial and antiviral interferon in lower vertebrates

Type Ⅳ interferon(IFN-υ)is a recently discovered cytokine crucial for host defense against viral infections.However,the role and mechanisms of IFN-υin bacterial infections remain unexplored.This study investigated the antibacterial and antiviral functions and mechanisms of grass carp(Ctenopharyngodon idella)IFN-υ(CiIFN-υ)both in vivo and in vitro.The CiIFN-υgene was first identified and characterized in grass carp.Subsequently,the immune expression of CiIFN-υsignificantly increased following bacterial challenge,indicating its response to bacterial infections.The eukaryotic recombinant expression plasmid of CiIFN-υwas then constructed and transfected into fathead minnow(FHM)cells.Supernatants were collected and incubated with four bacterial strains,followed by plate spreading and colony counting.Results indicated that CiIFN-υexhibited more potent antibacterial activity against gram-negative bacteria compared to gram-positive bacteria and aggregated gram-negative bacteria but not gram-positive bacteria.In vivo experiments further confirmed the antibacterial function,showing high survival rates,low tissue edema and damage,reduced tissue bacterial load,and elevated proinflammatory response at the early stages of bacterial infection.In addition,the antiviral function of CiIFN-υwas confirmed through in vitro and in vivo experiments,including crystal violet staining,survival rates,tissue viral burden,and reverse transcription-quantitative real-time polymerase chain reaction(RT-qPCR).This study highlights the antibacterial function and preliminary mechanism of IFN-υ,demonstrating that IFN-υpossesses dual functions against bacterial and viral infections.

Aromatic compounds from an aqueous extract of “ban lan gen” and their antiviral activities

A pair of new diphenyl glycerol ether enantiomers(-)-l and(+)-l and two new methyl benzamidobenzoates 2 and 3,named(-)-(R)-and(+)-(S)-isatindigotrioic acid[(-)-l and(+)-l]and isatindigoticamides A(2) and B(3),respectively,were isolated from an aqueous decoction of the roots of Isatis indigotica(ban lan gen).Their structures were elucidated by spectroscopic data analysis including2 D NMR experiments.The absolute configurations of(-)-l and(+)-l were assigned based on the CD exciton chirality method.Compounds 2 and 3 exhibited antiviral activities against HSV-1 with IC_(50)values of 4.87 and 25.87μmol/L,respectively.Compound 2 was also found active against Coxsackie virus B3 and LPS-induced NO production.

Synthesis and antiviral activities of novel 1,4-pentadien-3-one derivatives bearing an emodin moiety

A series of 1,5-diaryl-1,4-pentadien-3-one derivatives bearing an emodin group were designed and synthesized by the combination of natural products. The antiviral activities against tobacco mosaic virus（TMV） and cucumber mosaic virus（CMV） in vivo were evaluated. Some of the derivatives displayed promising curative effect and protective activity against TMV. Compound D5 showed appreciable curative bioactivity on TMV approximately of 50% at 306.2 mg/m L, which was superior to ningnanmycin（409.3 mg/m L）.

Synthesis and antiviral activities of a novel class of thioflavone and flavonoid analogues

A novel class of thioflavone and flavonoid derivatives has been prepared and their antiviral activities against enterovirus 71(EV71)and the coxsackievirus B3(CVB3)and B6(CVB6)were evaluated.Compounds 7d and 9b showed potent antiviral activities against EV71 with ICso values of 8.27 and 5.48μM,respectively.Compound 7f,which has been synthesized for the first time in this work,showed the highest level of inhibitory activity against both CVB3 and CVB6 with an ICso value of 0.62 and 0.87μM.Compounds 4b,7a,9c and 9e also showed strong inhibitory activities against both the CVB3 and CV B6 at low concentrations(IC_(50)=1.42-7.15μM),whereas compounds 4d,7c,7e and 7g showed strong activity against CVB6(IC_(50)=2.91-3.77μM)together with low levels of activity against CVB3.Compound 7d exhibited stronger inhibitory activity against CVB3(IC_(50)=6.44μM)thaln CVB6(IC_(50)>8.29μM).The thioflavone derivatives 7a,7c,7d,7e,7f and 7g,represent a new class of lead compounds for the development of novel antiviral agents.

Antiviral activity of mangiferin from the rhizome of Anemarrhena asphodeloides against herpes simplex virus type 1

Objective:To evaluate the antiviral activity of pure compounds against herpes simplex virus type 1(HSV-1)from the rhizome of Anemarrhena asphodeloides.Methods:Bioassay-guided isolation was conducted to separate the active compound and its chemical structure was elucidated by spectral analysis.In vitro antiviral efficacy of active compound was detected by Cell Counting Kit-8 assay,plaque reduction assay,and fluorescence observation.RT-PCR was used to determine the viral load and the cytokine-related gene expression after HSV-1 infection.In vivo study was also conducted to further determine antiviral efficacy of an active compound against HSV-1.Results:An active compound was isolated and elucidated as mangiferin.Mangiferin significantly inhibited the replication of HSV-1 in Vero cells with a half maximal inhibitory concentration(IC_(50))of 64.0 mg/L.Time-of-addition and time-of-removal assays demonstrated that mangiferin could effectively inhibit the replication of HSV-1 in the early stage(8 h).UL12,UL42,and UL54 gene expression levels of HSV-1 in the 64 mg/L mangiferin-treated group were markedly reduced as compared with the HSV-1 group(P<0.01).Fluorescence observation showed that mangiferin attenuated the mitochondrial damage maintainingΔΨm induced by HSV-1 in Vero cells.The expression of inflammatory factors TNF-α,IL-1β,and IL-6 was remarkably increased in the virus-infected group as compared with that in the normal group(P<0.05),the levels of these inflammatory factors dropped after treatment with mangiferin.Mangiferin significantly decreased the viral load and attenuated the HSV-1-induced up-regulation of TNF-α,IL-1β,and IL-6.The relative protection rate of HSV-1-infected mice could reach up to55.5%when the concentration of mangiferin was 4 g/kg.Conclusions:Mangiferin exhibits promising antiviral activity against HSV-1 in vitro and in vivo and could be a potential antiviral agent for HSV-1.

Pharmacodynamic study in multi-animal models on the efficacy and optimal dosage of antiviral oral liquid for children

Antiviral Oral Liquid(AOL)is an adult medicine in the Chinese Pharmacopoeia used to treat upper respiratory infections such as influenza.It has shown promising clinical efficacy in relieving flu-like symptoms such as fever,inflammation,and pharyngalgia both in adults and children.However,the instruction manual does not specify the exact usage and dosage of AOL for children.In this article,we set 6 dosage ranges:0.2,0.5,0.7,0.9,1.1,1.4 mL/kg/d,according to its dosage for adults and the conversion method between adult and children dosage.And six animal models were used to evaluate the effectiveness of AOL in different doses.The results indicated that AOL could reduce the lung index,virus load,and expression of proinflammatory cytokines in the lung.AOL could improve pathological changes and prolong the survival time of mice infected by the Influenza A virus(H1N1)A/PR/8/34 strains at 0.5–0.9 mL/kg/d concentrations in different degrees.The four dose groups of 0.7–1.4 mL/kg/d could significantly inhibit the ear shell swelling caused by xylene and reduce the rabbit body temperature induced by lipopolysaccharide(P<0.01,P<0.05).All the five dosage groups of 0.2–1.1 mL/kg/d could inhibit the increase of peritoneal capillary permeability induced by glacial acetic acid(P<0.01).AOL at 0.7 and 0.9 mL/kg/d reduced the painful writhing times in young mice induced by glacial acetic(P<0.01).These results indicated that the optimal dose of AOL in antiviral,antipyretic,anti-inflammatory,and analgesic effects is 0.7 mL/kg/d.

Physicochemical Characters of rPoIFN-α and Its Antiviral Activity in vitro

[Objective]The research aimed to test and identify the physicochemical characters and antiviral activity in vitro of semi-finished product of the recombinant porcine rPoIFN-α. [Method]HEp-2/VSV system was used to test the antiviral activity of three batches of rPoIFN-α. Using recombinant human IFN-α as reference,the titer of interferon was measured. The semi-finished product of rPoIFN-α with the known titer were treated with 0.25% trypsin,HCl and mouse anti-porcine IFN-α monoclonal antibody. And the anti-viral activity of each batch of rPoIFN-α was detected. The physicochemical characters of rPoIFN-α were evaluated. The inhibition of induced cytopathic effect of rPoIFN-α on PPV （Porcine parvovirus） and PRV （Porcine pseudorabies） on swine kidney cell （PK-15） was determined. And the antiviral activity of rPoIFN-α in vitro was observed. [Result]The titers of semi-finished products of rPoIFN-α titrated by HEp-2/VSV system could reach 1.5×105 IU/ml,with the specific activity of 1.1×106 IU/mg. The residual rate of the tier of rPoIFN-α treated by 0.25% trypsin at 37 ℃ for 1 h was less than 1%. And that treated with HCl （pH of 2.0） for 72 h was up to 95%. And that treated at 56 ℃ for 30 min and that treated by mouse anti-porcine IFN-α monoclonal antibody at 37 ℃ for 1 h were higher than 47% and about 1% respectively. The antiviral test in vitro showed that 50 and 500 IU/ml rPoIFN-α could inhibit the induced cytopathic effect of PRV and PPV on PK-15 cell lines. [Conclusion]rPoIFN-α had the basic physicochemical characters of IFN-α. And it could inhibit the induced cytopathic effect of PRV and PPV on PK-15 cell lines,but there was dosage difference.

A bacterial protein Rhp-PSP inhibits plant viral proliferation through endoribonuclease activity

Plant virus causes massive crop losses globally.However,there is currently no effective measure to control plant viral disease.Previously,we identify an antiviral protein Rhp-PSP,produced by the bacterial Rhodopseudomonas palustris strain JSC-3b.In this study,we discover that the antiviral activity of Rhp-PSP relies on its endoribonuclease activity.Converting the arginine(R)residue at position 129 onto alanine(A)abolishs its endoribonuclease activity on coat protein(CP)RNA of tobacco mosaic virus(TMV),consequentially,compromises the antiviral activity of Rhp-PSP.Further investigation demonstrates that,the mutant Rhp-PSP^(R129A)is unable to form the homotrimer as the wild type,indicating the importance of quaternary junction for the endoribonuclease activity.Overexpression of Rhp-PSP in Nicotiana benthamiana significantly enhances the resistance against TMV of seedlings,while expression of Rhp-PSP^(R129A)did not,confirming that endoribonuclease activity is responsible for the antiviral activity of Rhp-PSP.In addition,foliar spray of Rhp-PSP solution on tomato and pepper plants significantly reduces the disease index of viral diseases,indicating that Rhp-PSP shows potential to develop antiviral agent in practice.

Inhibition of hepatitis B virus via selective apoptosis modulation by Chinese patent medicine Liuweiwuling Tablet

BACKGROUND Liuweiwuling Tablet(LWWL)is a Chinese patent medicine approved for the treatment of chronic inflammation caused by hepatitis B virus(HBV)infection.Previous studies have indicated an anti-HBV effect of LWWL,specifically in terms of antigen inhibition,but the underlying mechanism remains unclear.AIM To investigate the potential mechanism of action of LWWL against HBV.METHODS In vitro experiments utilized three HBV-replicating and three non-HBV-replicating cell lines.The in vivo experiment involved a hydrodynamic injectionmediated mouse model with HBV replication.Transcriptomics and metabolomics were used to investigate the underlying mechanisms of action of LWWL.RESULTS In HepG2.1403F cells,LWWL(0.8 mg/mL)exhibited inhibitory effects on HBV DNA,hepatitis B surface antigen and pregenomic RNA(pgRNA)at rates of 51.36%,24.74%and 50.74%,respectively.The inhibition rates of LWWL(0.8mg/mL)on pgRNA/covalently closed circular DNA in HepG2.1403F,HepG2.2.15 and HepG2.A64 cells were 47.78%,39.51%and 46.74%,respectively.Integration of transcriptomics and metabolomics showed that the anti-HBV effect of LWWL was primarily linked to pathways related to apoptosis(PI3K-AKT,CASP8-CASP3 and P53 pathways).Apoptosis flow analysis revealed that the apoptosis rate in the LWWL-treated group was significantly higher than in the control group(CG)among HBV-replicating cell lines,including HepG2.2.15(2.92%±1.01%vs 6.68%±2.04%,P<0.05),HepG2.A64(4.89%±1.28%vs 8.52%±0.50%,P<0.05)and HepG2.1403F(3.76%±1.40%vs 7.57%±1.35%,P<0.05)(CG vs LWWL-treated group).However,there were no significant differences in apoptosis rates between the non-HBV-replicating HepG2 cells(5.04%±0.74%vs 5.51%±1.57%,P>0.05),L02 cells(5.49%±0.80%vs 5.48%±1.01%,P>0.05)and LX2 cells(6.29%±1.54%vs 6.29%±0.88%,P>0.05).TUNEL staining revealed a significantly higher apoptosis rate in the LWWL-treated group than in the CG in the HBVreplicating mouse model,while no noticeable difference in apoptosis rates between the two groups was observed in the non-HBV-replicating mouse model.CONCLUSION Preliminary results suggest that LWWL exerts a potent inhibitory effect on wild-type and drug-resistant HBV,potentially involving selective regulation of apoptosis.These findings offer novel insights into the anti-HBV activities of LWWL and present a novel mechanism for the development of anti-HBV medications.

High-Value-Added Utilization of Turpentine:Screening of Anti-Influenza Virus Agents fromβ-Pinene Derivatives

Turpentine is a renewable and resourceful forest product.The deep processing and utilization of turpentine,particularly its primary componentβ-pinene,has garnered widespread attention.This study aimed to synthesize 40 derivatives ofβ-pinene,including nopinone,3-cyanopyridines of nopinone,myrtanyl acid,myrtanyl acylthioureas,and myrtanyl amides.We assessed the antiviral activities of theseβ-pinene derivatives against influenza virus A/Puerto Rico/8/34(H1N1)using the 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.Theβ-pinene derivatives were used before and after cellular infection with the influenza virus to evaluate their preventive and therapeutic effects against the H1N1 virus.The results showed that only compound 10o exhibited a preventive effect against the H1N1 virus with a half-maximal inhibitory concentration(IC50)value of 47.6μmol/L.Among the compounds,4e,4i,and 4l demonstrated therapeutic effects against cellular infection,with compound 4e displaying the most potent therapeutic effect(IC50=17.5μmol/L),comparable to the positive control ribavirin.These findings indicated that certainβ-pinene derivatives exhibited in vitro antiviral activity against the H1N1 influenza A virus,warranting further investigation as potential anti-influenza agents.

In Vitro Anti-influenza Virus Activities of Sulfated Polysaccharide Fractions from Gracilaria lemaneiformis

In this paper, in vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiforrnis were investigated. Cytotoxicities and antiviral activities of Gracilaria lemaneiformis polysaccharides （PGL）, Gracilaria lemaneiformis polysaccharide fraction-1 （GL-1）, Gracilaria lemaneiformis polysaccharide fraction-2 （GL-2） and Gracilaria lemaneiformis polysaccharide fraction-3 （GL-3） were studied by the Methyl thiazolyl tetrazolium （MTT） method, and the inhibitory effect against Human influenza virus H1-364 induced cytopathic effect （CPE） on MDCK cells were observed by the CPE method. In addition, the antiviral mechanism of PGL was explored by Plaque forming unit （PFU）, MTT and CPE methods. The results showed： i） Cytotoxicities were not significantly revealed, and H1-364 induced CPE was also reduced treated with sulfated polysaccharide fractions from Gracilaria lemaneiformis; ii） Antiviral activities were associated with the mass percentage content of sulfate groups in polysaccharide fractions, which was about 13%, in polysaccharides （PGL and GL-2） both of which exhibited higher antiviral activity; iii） A potential antiviral mechanism to explain these observations is that viral adsorption and replication on host cells were inhibited by sulfated polysaccharides from Gracilaria lemaneiformis. In conclusion, Anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were revealed, and the antiviral activities were associated with content of sulfate groups in polysaccharide fractions

Antiviral Activity of the Effective Monomers from Folium Isatidis Against Influenza Virus in Vivo

In order to evaluate the anti-influenza virus activity of the effective monomer from Folium Isatidis (FI) in vivo,we established mice model with viral pneumonia and divided them into 3 different dose groups,then observed their lung indexes,pulmonary pathological changes,pulmonary virus hemagglitination titers,living time and death rates.The results showed that the monomer could reduce the pulmonary index from 2.64 to 1.93,1.63 and 1.40 (P<0.01) and decrease the hemagglitination titer from 1.15 to 0.84,0.70 and 0.59 (P<0.01).In addition,different groups of FI could significantly lessen the mortality rate from 100% to 30%,25% and 15%,and prolong the living time from 5.1d to 6.5d,8.4d and 8.9d respectively(P<0.01).The high dose (75 mg/kg/d) has the similar effect with 100 mg/kg/d dose of virazole(P>0.05),and more effective than 200 mg/kg/d dose of antiviral liquor (P<0.05).

Antiviral active peptide from oyster

An active peptide against herpes virus was isolated from the enzymic hydrolysate of oyster(Crassostrea gigas) and purified with the definite direction hydrolysis technique in the order of alcalase and bromelin.The hydrolysate was fractioned into four ranges of molecular weight(>10 kDa,10-5 kDa,5-1 kDa and <1 kDa) using ultrafiltration membranes and dialysis.The fraction of 10-5 kDa was purified using consecutive chromatographic methods including DEAE Sephadex A-25 column,Sephadex G-25 column,and high performance liquid chromatogram(HPLC) by activity-guided isolation.The antiviral effect of the obtained peptide on herpetic virus was investigated in Vero cells by observing cytopathic effect(CPE).The result shows that the peptide has high inhibitory activity on herpetic virus.

Antiviral Activity of GuiQi Polysaccharides against Enterovirus 71 in vitro

In this study,we have investigated the antiviral activity of GuiQi polysaccharides (GQP) upon enterovirus 71 (EV71) in vitro.An assay using methyl thiazolyl tetrazolium (MTT),and analyses of cytopathic effects (CPE)were used to examine the antiviral activity of GQP upon Vero cells infected with EV71.The results revealed that GQP at concentrations below 31.2μg/mL exhibited significant antiviral effects upon EV71 when applied under three different experimental protocols.GQP was most strongly active in preventing the adsorption of EV71 to target cells and in this respect it was significantly more effective than ribavirin.In addition,it was clear that GQP could inhibit viral replication when added to cells 2 h after infection,but if added at the point of infection its effect was weak.GQP is considered to be less toxic than ribavirin,and may warrant further evaluation as a possible agent in the treatment of hand,foot and mouth disease (HFMD).

Antiviral activity of five Asian medicinal pant crude extracts against highly pathogenic H5N1 avian influenza virus

Objective: To study the antiviral properties of the five Asian medicinal plants against in vitro infection by the highly pathogenic avian influenza virus(H5N1).Methods: Crude extracts of Andrographis paniculata, Curcuma longa(C. longa),Gynostemma pentaphyllum, Kaempferia parviflora(K. parviflora), and Psidium guajava obtained by both water and ethanol extractions were investigated for their cytotoxicity in the Madin–Darby canine kidney cells. Thereafter, they were investigated in vitro for antiviral activity and cytokine response upon H5N1 virus infection.Results: The results revealed that both water and ethanol extracts of all the five studied plants showed significant antiviral activity against H5N1 virus. Among these plants,C. longa and K. parviflora showed strong anti-H5N1 activity. Thus, they were selected for further studies on their cytokine response upon virus infection. It was found that ethanol and water crude extracts of C. longa and K. parviflora induced significant upregulation of TNF-a and IFN-b m RNA expressions, suggesting their roles in the inhibition of H5N1 virus replication.Conclusions: To the best of the authors' knowledge, this study is among the earliest reports to illustrate the antiviral property of these Asian medicinal plants against the highly pathogenic avian H5N1 influenza virus. The results of this study shed light on alternative therapeutic sources for treatment of H5N1 influenza virus infection in the future.

Antifeedant and Antiviral Diterpenoids from the Fresh Roots of Euphorbia jolkinii

The perennial herbaceous plant Euphorbia jolkinii(Euphorbiaceae)is a noxious weed widely distributed in the grasslands of northwestern Yunnan and has greatly threatened the local biodiversity.Phytochemical investigation on the fresh roots of E.jolkinii afforded six new diterpenoids 1,2,4–6,and 8,together with fifteen known diterpenoids.Their structures were elucidated on the basis of 1D and 2D NMR and other spectroscopic methods.Casbane,lathyrane,abietane,and ent-kaurane diterpenoids were reported from this plant for the first time.Selected compounds were evaluated for their antifeedant and anti-RSV(respiratory syncytial virus)activities.Compound 2 and ingenol(3)exhibited moderate antifeedant activity against a generalist insect herbivore,Spodoptera exigua,with EC50 values of 17.88 and 17.71 lg/cm2 respectively.Compound 19 showed significant anti-RSV activity,with 50%inhibition(IC50)value of 10.0 lM and selective index of 8.0.Compounds 1 and 2 were less active against RSV virus,both with IC50 value of 25 lM,and with selective indices of 1.0 and 3.2 respectively.These findings provided new evidence for the biological functions and utilization of the diversified diterpenoid metabolites in the roots of this rich but harmful plant.

Antiviral Activity of Recombinant Cyanovirin-N against HSV-1

In this study,a standard strain of HSV-1 (strain SM44) was used to investigate the antiviral activity of the recombinant Cyanovirin-N (CV-N) against Herpes simplex virus type 1 (HSV-1) in vitro and in vivo.Cytopathic effect (CPE) and MTT assays were used to evaluate the effect of CV-N on HSV-1 in Vero cells.The number of copies of HSV-DNA was detected by real-time fluorescence quantitative PCR (FQ-PCR).The results showed that CV-N had a low cytotoxicity on Vero cells with a CC50 of 359.03±0.56 μg/mL,and that it could not directly inactivate HSV-1 infectivity.CV-N not only reduced the CPE of HSV-1 when added before or after viral infection,with a 50% inhibitory concentration (IC50) with 2.26 and 30.16μg/mL respectively,but it also decreased the copies of HSV-1 DNA in infected host cells.The encephalitis model for HSV-1 infection was conducted in Kunming mice,and treated with three dosages of CV-N (0.5,5 & 10 mg/kg) which was administered intraperitoneally at 2h,3d,5d,7d post infection.The duration for the appearance of symptoms of encephalitis and the survival days were recorded and brain tissue samples were obtained for pathological examination (HE staining).Compared with the untreated control group,in the 5mg/kg CV-N and 10mg/kg CV-N treated groups,the mice suffered light symptoms and the number of survival days were more than 9d and 14d respectively.HE staining also showed that in 5mg/kg CV-N and 10mg/kg CV-N treated groups,the brain cells did not show visible changes,except for a slight inflammation.Our results demonstrated that CV-N has pronounced antiviral activity against HSV-1 both in vitro and in vivo,and it would be a promising new candidate for anti-HSV therapeutics.

Antiviral Activity of Dual-acting Hydrocarbon-stapled Peptides against HIV-1 Predominantly Circulating in China

Objective New rationally designed i,i＋7-hydrocarbon-stapled peptides that target both HIV-1 assembly and entry have been shown to have antiviral activity against HIV-1 subtypes circulating in Europe and North America. Here, we aimed to evaluate the antiviral activity of these peptides against HIV-1 subtypes predominantly circulating in China. Methods The antiviral activity of three i,i＋7-hydrocarbon-stapled peptides, NYAD-36, NYAD-67, and NYAD-66, against primary HIV-1 CRF07_BC and CRFOI_AE isolates was evaluated in peripheral blood mononuclear cells （PI3MCs）. The activity against the CRF07_BC and CRF01_AE Env-pseudotyped viruses was analyzed in TZM-bl cells. Results We found that all the stapled peptides were effective in inhibiting infection by all the primary HIV-1 isolates tested, with 50% inhibitory concentration toward viral replication （ICso） in the low micromolar range. NYAD-36 and NYAD-67 showed better antiviral activity than NYAD-66 did. We further evaluated the sensitivity of CRF01_AE and CRF07_BC Env-pseudotyped viruses to these stapled peptides in a single-cycle virus infectivity assay. As observed with the primary isolates, the ICs0s were in the low micromolar range, and NYAD-66 was less effective than NYAD-36 and NYAD-67. Conclusion Hydrocarbon-stapled peptides appear to have broad antiviral activity against the predominant HIV-1 viruses in China. This finding may provide the impetus to the rational design of peptides for future antiviral therapy.