Plaque Inhibition Assay Research Articles

Screening and verification of antiviral compounds against HSV-1 using a method based on a plaque inhibition assay

BackgroundHerpes simplex virus type 1 (HSV-1) infection is a common viral disease that mainly causes oral lesions, but can also cause genital lesions in some instances. Current treatments with nucleoside analogs are limited by the emergence of drug resistance. Therefore, novel anti-HSV-1 drugs are urgently needed.MethodsIn this study, we screened a library of 2080 compounds for anti-HSV-1 activity using a plaque formation assay. We selected 11 potential inhibitors of HSV-1 and further evaluated their antiviral effects by plaque reduction assay and real-time polymerase chain reaction (qPCR).ResultsFive compounds, namely ginsenoside Rd, brassinolide, rosamultin, 3’-hydroxy puerarin, and clinafloxacin HCl, showed potent anti-HSV-1 activity and completely suppressed plaque formation at a concentration of 10 µM. Among them, clinafloxacin HCl, a fluoroquinolone antibiotic, exhibited a high selectivity index for HSV-1.ConclusionsOur findings suggest that these five compounds have potential antiviral properties against HSV-1 and may have different mechanisms of action. Further studies are warranted to elucidate the antiviral mechanisms of these compounds and to explore their therapeutic potential for HSV-1 infection.

Design, Synthesis, Molecular Docking Analysis and Biological Evaluations of 4-[(Quinolin-4-yl)amino]benzamide Derivatives as Novel Anti-Influenza Virus Agents.

In this study, a series of 4-[(quinolin-4-yl)amino]benzamide derivatives as the novel anti-influenza agents were designed and synthesized. Cytotoxicity assay, cytopathic effect assay and plaque inhibition assay were performed to evaluate the anti-influenza virus A/WSN/33 (H1N1) activity of the target compounds. The target compound G07 demonstrated significant anti-influenza virus A/WSN/33 (H1N1) activity both in cytopathic effect assay (EC50 = 11.38 ± 1.89 µM) and plaque inhibition assay (IC50 = 0.23 ± 0.15 µM). G07 also exhibited significant anti-influenza virus activities against other three different influenza virus strains A/PR/8 (H1N1), A/HK/68 (H3N2) and influenza B virus. According to the result of ribonucleoprotein reconstitution assay, G07 could interact well with ribonucleoprotein with an inhibition rate of 80.65% at 100 µM. Furthermore, G07 exhibited significant activity target PA−PB1 subunit of RNA polymerase according to the PA−PB1 inhibitory activity prediction by the best pharmacophore Hypo1. In addition, G07 was well drug-likeness based on the results of Lipinski’s rule and ADMET prediction. All the results proved that 4-[(quinolin-4-yl)amino]benzamide derivatives could generate potential candidates in discovery of anti-influenza virus agents.

Screening and Verification of Antiviral Compounds Against HSV-1 Using a Method Based on an Improved Plaque Inhibition Assay

Screening and Verification of Antiviral Compounds Against HSV-1 Using a Method Based on an Improved Plaque Inhibition Assay

Abstract LB179: Oncolytic virus TG6002 locates to tumors after intravenous infusion and induces tumor-specific expression of a functional pro-drug activating enzyme in patients with advanced gastrointestinal carcinomas

Abstract Objective: TG6002 is a vaccinia virus deleted for Thymidine Kinase/Ribonucleotide Reductase and encoding the FCU1 enzyme that converts 5-Fluorocytosine (5-FC) to 5-Fluorouracil (5-FU). In a dose-escalation phase I study combining intravenous TG6002 and oral 5-FC in patients with advanced gastrointestinal carcinomas, exploratory analyses were performed to document TG6002 pharmacokinetic (PK) and biodistribution, and FCU1 function. Methodology: A total of 10 patients, median age 60 years (range 50-69), received TG6002 infusions on days 1, 8 and 15 at the dose of 3x108 pfu (n=3) (low dose, LD) or 1x109 pfu (high dose, HD) (n=7) combined with 5-FC (4 times 50 mg/kg/day) on days 5 to 7, 12 to 14, and 19 to 28 for colorectal (n=6), esophagus (n=1), gastric (n=1), pancreatic (n=1) and ampulla of Vater (n=1) carcinomas. Blood was sampled 30 min, 3h and 24h after TG6002 infusion on day 1 and 15 for plasma TG6002 PK and one hour after intake of 5-FC at screening (single dose of 50 mg/kg) and on days 5, 7, 14 and 28 for serum 5-FC and 5-FU measurements. A metastasis biopsy was performed on day 5 along with synchronous blood sampling. Virus presence was assessed by qPCR and plaque assay, and 5-FC and 5-FU quantified using HPLC-MS. Neutralizing antibodies (NAb) titers were assessed using a plaque inhibition assay at baseline, days 28 and 43. Results: TG6002 was detected by qPCR in plasma and was rapidly cleared with no patients showing trace of the virus beyond 3 hours after administration. On day 5, despite very scarce availability of biomaterial, the virus was detected in tumoral tissue in 1/3 and 2/7 patients of the LD and HD cohorts, respectively. 5-FC to 5-FU conversion was detected in tumor of all patients and the highest tumor concentrations of 5-FU (65 and 227 pg/mg of tissue, respectively) were found in 2 of the 3 patients in which virus was detected in the tumor. The other patients had tumor 5-FU concentrations ranging from 0.8 to 8.7 pg/mg. Those patients with highest tumor 5-FU levels had the highest level of serum 5-FU on day 5 (352 and 417 ng/mL, respectively). All other patients had levels of 5-FU ranging from 2 to 42 ng/mL, reflecting FCU1 activity. No 5-FU was detected after the intake of 5-FC during the screening period, excluding endogenous 5-FC to 5-FU conversion. Overall, blood 5-FU concentrations were 89±144, 50±96, 7±9 and 1±0.6 ng/ml on days 5, 7, 14 and 28, respectively, with no apparent differences between LD and HD cohorts. NAbs were developed by all patients on day 28 and could explain the decrease in blood 5-FU over the study course. In conclusion, despite the sensitivity challenges associated with direct detection of viral particles in patient tumor tissue, our data suggest that TG6002 locates to tumors after intravenous administration, remains active and effectively express an active recombinant payload selectively in tumor tissue. The study is continuing with escalating doses of virus. Citation Format: Kaidre Bendjama, Philippe Cassier, Victor Moreno, Bernard Doger, Emiliano Calvo, Maria de Miguel, Christiane Jungels, Philippe Erbs, Damien Carpentier, Alain Sadoun. Oncolytic virus TG6002 locates to tumors after intravenous infusion and induces tumor-specific expression of a functional pro-drug activating enzyme in patients with advanced gastrointestinal carcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB179.

Unfractionated heparin inhibits live wild type SARS-CoV-2 cell infectivity at therapeutically relevant concentrations.

Background and PurposeCurrently, there are no licensed vaccines and limited antivirals for the treatment of COVID‐19. Heparin (delivered systemically) is currently used to treat anticoagulant anomalies in COVID‐19 patients. Additionally, in the United Kingdom, Brazil and Australia, nebulised unfractionated heparin (UFH) is being trialled in COVID‐19 patients as a potential treatment. A systematic comparison of the potential antiviral effect of various heparin preparations on live wild type SARS‐CoV‐2, in vitro, is needed.Experimental ApproachSeven different heparin preparations including UFH and low MW heparins (LMWH) of porcine or bovine origin were screened for antiviral activity against live SARS‐CoV‐2 (Australia/VIC01/2020) using a plaque inhibition assay with Vero E6 cells. Interaction of heparin with spike protein RBD was studied using differential scanning fluorimetry and the inhibition of RBD binding to human ACE2 protein using elisa assays was examined.Key ResultsAll the UFH preparations had potent antiviral effects, with IC50 values ranging between 25 and 41 μg·ml−1, whereas LMWHs were less inhibitory by ~150‐fold (IC50 range 3.4–7.8 mg·ml−1). Mechanistically, we observed that heparin binds and destabilizes the RBD protein and furthermore, we show heparin directly inhibits the binding of RBD to the human ACE2 protein receptor.Conclusion and ImplicationsThis comparison of clinically relevant heparins shows that UFH has significantly stronger SARS‐CoV‐2 antiviral activity compared to LMWHs. UFH acts to directly inhibit binding of spike protein to the human ACE2 protein receptor. Overall, the data strongly support further clinical investigation of UFH as a potential treatment for patients with COVID‐19.

A pilot study of the antiviral activity of anionic and cationic polyamidoamine dendrimers against the Middle East respiratory syndrome coronavirus.

The Middle East respiratory syndrome coronavirus (MERS‐CoV) is an emerging virus that causes infection with a potentially fatal outcome. Dendrimers are highly branched molecules that can be added to antiviral preparations to improve their delivery, as well as their intrinsic antiviral activity. Studies on identifying anti‐MERS‐CoV agents are few. Three types of polyanionic dendrimers comprising the terminal groups sodium carboxylate (generations 1.5, 2.5, 3.5, and 4.5), hydroxyl (generations 2, 3, 4, and 5), and succinamic acid (generations 2, 3, 4, and 5) and polycationic dendrimers containing primary amine (generations 2, 3, 4, and 5) were used to assess their antiviral activity with the MERS‐CoV plaque inhibition assay. The hydroxyl polyanionic set showed a 17.36% to 29.75% decrease in MERS‐CoV plaque formation. The most potent inhibition of MERS‐CoV plaque formation was seen by G(1.5)‐16COONa (40.5% inhibition), followed by G(5)‐128SA (39.77% inhibition). In contrast, the cationic dendrimers were cytotoxic to Vero cells. Polyanionic dendrimers can be added to antiviral preparations to improve the delivery of antivirals, as well as the intrinsic antiviral activity.

Synthesis, characterization and biological activity studies on amide derivatives

DOI : 10.26650/IstanbulJPharm.2018.18007 In this study, with intent to find out novel anti-biofilm and antiviral agents, a series of amide derivatives were synthesized and their structures were elucidated by FT-IR and 1H-NMR and 13C-NMR and MS methods. And also, their purity were proven by TLC, HPLC and elemental analyses. And finally, the synthesized compounds were examined for their biofilm formation and swarming motility inhibitory activities in P. aeruginosa PA01. These compounds were found to reduce biofilm formation by 8.7-25.6% and swarming motility by 18.3-33.8% in P. aeruginosa PA01 at a concentration of 200 μM. Besides, all of the compounds were evaluated for their antiviral activity against influenza A viruses. The plaque inhibition assays indicated that compound 6 (N-(4-{[5-(ethylamino)-1,3,4-thiadiazol-2-yl]methyl}phenyl)-4- fluorobenzamide) has considerable inhibitory effect on influenza A virus plaque formation.

Anti-influenza A virus activity of rhein through regulating oxidative stress, TLR4, Akt, MAPK, and NF-κB signal pathways.

Rhein, an anthraquinone compound existing in many traditional herbal medicines, has anti-inflammatory, antioxidant, antitumor, antiviral, hepatoprotective, and nephroprotective activities, but its anti-influenza A virus (IAV) activity is ambiguous. In the present study, through plaque inhibition assay, time-of-addition assay, antioxidant assay, qRT-PCR, ELISA, and western blotting assays, we investigated the anti-IAV effect and mechanism of action of rhein in vitro and in vivo. The results showed that rhein could significantly inhibit IAV adsorption and replication, decrease IAV-induced oxidative stress, activations of TLR4, Akt, p38, JNK MAPK, and NF-κB pathways, and production of inflammatory cytokines and matrix metalloproteinases in vitro. Oxidant H2O2 and agonists of TLR4, Akt, p38/JNK and IKK/NF-κB could significantly antagonize the inhibitory effects of rhein on IAV-induced cytopathic effect (CPE) and IAV replication. Through an in vivo test in mice, we also found that rhein could significantly improve the survival rate, lung index, pulmonary cytokines, and pulmonary histopathological changes. Rhein also significantly decreased pulmonary viral load at a high dose. In conclusion, rhein can inhibit IAV adsorption and replication, and the mechanism of action to inhibit IAV replication may be due to its ability to suppress IAV-induced oxidative stress and activations of TLR4, Akt, p38, JNK MAPK, and NF-κB signal pathways.

Emodin Inhibition of Influenza A Virus Replication and Influenza Viral Pneumonia via the Nrf2, TLR4, p38/JNK and NF-kappaB Pathways

Lasting activations of toll-like receptors (TLRs), MAPK and NF-κB pathways can support influenza A virus (IAV) infection and promote pneumonia. In this study, we have investigated the effect and mechanism of action of emodin on IAV infection using qRT-PCR, western blotting, ELISA, Nrf2 luciferase reporter, siRNA and plaque inhibition assays. The results showed that emodin could significantly inhibit IAV (ST169, H1N1) replication, reduce IAV-induced expressions of TLR2/3/4/7, MyD88 and TRAF6, decrease IAV-induced phosphorylations of p38/JNK MAPK and nuclear translocation of NF-κB p65. Emodin also activated the Nrf2 pathway, decreased ROS levels, increased GSH levelss and GSH/GSSG ratio, and upregulated the activities of SOD, GR, CAT and GSH-Px after IAV infection. Suppression of Nrf2 via siRNA markedly blocked the inhibitory effects of emodin on IAV-induced activations of TLR4, p38/JNK, and NF-κB pathways and on IAV-induced production of IL-1β, IL-6 and expression of IAV M2 protein. Emodin also dramatically increased the survival rate of mice, reduced lung edema, pulmonary viral titer and inflammatory cytokines, and improved lung histopathological changes. In conclusion, emodin can inhibit IAV replication and influenza viral pneumonia, at least in part, by activating Nrf2 signaling and inhibiting IAV-induced activations of the TLR4, p38/JNK MAPK and NF-κB pathways.

Generation of recombinant bovine interferon tau in the human embryonic kidney cell line and its biological activity

The objective of this study was to generate recombinant bovine interferon tau (rbIFNT) in mammalian hosts. The complementary DNA encoding bovine IFNT2 was cloned for the construction of pRcRSV-bIFNT2 expression vector. The expression vector was transfected to 293 cells. Transfected cells harboring expression vector were selected with G418. Highly expressing clonal line was adapted to serum-free suspension culture in a spinner flask. The recombinant protein had 24 kDa apparent molecular mass, suggesting being expressed as a glycoprotein, and was purified from serum-free conditioned medium by the combination of Diethylaminoethanol Sepharose ion exchange and Sephacryl S-200 HR gel filtration. A total of 7.3 mg rbIFNT was obtained from 13.5L conditioned medium. Generated rbIFNT was biologically active in terms of antiviral activity measured by the plaque inhibition assay with Madin-Darby bovine kidney cells and the vesicular stomatitis virus. The recombinant protein was also utilized for immunization to raise antibodies in the rabbit. The generated antibody was capable of use in both Western blotting and the binding assay. The results in the present study suggest that a certain amount of rbIFNT is raised in mammalian hosts by using conventional plasmid vector and its antibody provides useful tools for studies in the biology of bovine IFNT.

Characterization and mechanisms of anti-influenza virus metabolites isolated from the Vietnamese medicinal plant Polygonum chinense

BackgroundPolygonum chinense Linn. is a common medicinal plant in Southeast Asia and has been used in traditional medicine in Vietnam. The plant contains phytochemicals with various biological properties; however, its antiviral effect has not yet been demonstrated. This study was aimed to evaluate the anti-influenza virus activity of crude extracts of P. chinense, to characterize antiviral metabolites therefrom and to investigate their mechanisms of antiviral action.MethodsThe methanol (MeOH) extract and organic solvent layers of P. chinense were prepared by extraction and partition with relevant solvents. The ethyl acetate (EtOAc) layer showing antiviral activity was chromatographed repeatedly on SiO2 and Sephadex LH-20 columns to give eight pure metabolites. Their chemical structures were determined by NMR and MS spectral data. Anti-influenza virus activity of the eight metabolites against virus strains A/Puerto Rico/8/34 (H1N1, PR8), A/Hong Kong/8/68 (H3N2, HK) and B/Lee/40 (Lee) was evaluated on the basis of cytopathic effect (CPE) and plaque inhibition assays. Time-of-addition, confocal microscopy and neuraminidase inhibition assay were performed for mode-of-action studies of active ingredients.ResultsThe MeOH extract of P. chinense showed anti-influenza virus activity with EC50 values ranging from 38.4 to 55.5 μg/mL in a CPE inhibition assay. Among the eight pure metabolites isolated from P. chinense, ellagic acid (PC5), methyl gallate (PC7) and caffeic acid (PC8) significantly inhibited viral replication in a dose-dependent manner in both plaque inhibition and CPE inhibition assays with EC50 values ranging from 14.7 to 81.1 μg/mL and CC50 values higher than 300 μg/mL. Mode-of-action studies suggested that PC5 and PC7 suppress virus entry into or replication in cells, while PC8 targets influenza viral neuraminidase, even oseltamivir-resistant one.ConclusionThese results demonstrated that P. chinense and its metabolites possess effective anti-influenza virus activities. The botanical materials of P. chinense could be a promising multitargeted inhibitor of influenza A and B viruses and applied to development of a novel herbal medicine.

Antiviral and virucidal activities of Duabanga grandiflora leaf extract against Pseudorabies virus in vitro.

BackgroundDuabanga grandiflora or known in Malaysia as Berembang Bukit, Megawasih, or Pedada Bukit, is a native plant of the Southeast Asian countries. In this study, the anti-viral properties of D. grandiflora were investigated.MethodsThe D. grandiflora leaf extracts were obtained with ethyl acetate, hexane, and ethanol as solvents and labelled 37 leaf ethyl acetate (37 L EA), 37 leaf hexane (37 L H), 37 leaf ethanol (37 L ET), respectively. The cytotoxicity of the extracts on Vero cells were determined by the 3-(4,5-Diamethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay.ResultsAmong extracts, 37 L EA was most cytotoxic to Vero cells, followed by 37 L H and 37 L ET, with CC50 of 218, 833, and >1000 μg/mL, respectively. The cytopathic effect (CPE) and plaque reduction, inhibition, and virucidal assays and the selective index (SI) were employed to determine the effect of the extracts on infectivity and replication of pseudorabies virus (PrV) in Vero cells. The D. grandiflora leaf extracts showed dose-dependent antiviral activities, with higher activities at high doses. The 37 L ET and 37 L EA showed anti-viral effects through plaque formation and viral replication inhibitions, and virucidal property. The SI of the 37 L ET and 37 L EA by the viral replication inhibition assay was 8.3 and 1.9, respectively, and by the CPE reduction assay, 6.7 and 2.9, respectively.ConclusionEthanol is the best solvent for the preparation of D. grandiflora leaf extract as an antiviral agent.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-016-1120-2) contains supplementary material, which is available to authorized users.

The significance of naturally occurring neuraminidase quasispecies of H5N1 avian influenza virus on resistance to oseltamivir: a point of concern.

Viral adaptability and survival arise due to the presence of quasispecies populations that are able to escape the immune response or produce drug-resistant variants. However, the presence of H5N1 virus with natural mutations acquired without any drug selection pressure poses a great threat. Cloacal samples collected from the 2004-2005 epidemics in Thailand from Asian open-billed storks revealed one major and several minor quasispecies populations with mutations on the oseltamivir (OTV)-binding site of the neuraminidase gene (NA) without prior exposure to a drug. Therefore, this study investigated the binding between the NA-containing novel mutations and OTV drug using molecular dynamic simulations and plaque inhibition assay. The results revealed that the mutant populations, S236F mutant, S236F/C278Y mutant, A250V/V266A/P271H/G285S mutant and C278Y mutant, had a lower binding affinity with OTV as compared with the WT virus due to rearrangement of amino acid residues and increased flexibility in the 150-loop. This result was further emphasized through the IC50 values obtained for the major population and WT virus, 104.74 nM and 18.30 nM, respectively. Taken together, these data suggest that H5N1 viruses isolated from wild birds have already acquired OTV-resistant point mutations without any exposure to a drug.

Development of three triplex real-time reverse transcription PCR assays for the qualitative molecular typing of the nine serotypes of African horse sickness virus

Blood samples collected as part of routine diagnostic investigations from South African horses with clinical signs suggestive of African horse sickness (AHS) were subjected to analysis with an AHS virus (AHSV) group specific reverse transcription quantitative polymerase chain reaction (AHSV RT-qPCR) assay and virus isolation (VI) with subsequent serotyping by plaque inhibition (PI) assays using AHSV serotype-specific antisera. Blood samples that tested positive by AHSV RT-qPCR were then selected for analysis using AHSV type specific RT-qPCR (AHSV TS RT-qPCR) assays. The TS RT-qPCR assays were evaluated using both historic stocks of the South African reference strains of each of the 9 AHSV serotypes, as well as recently derived stocks of these same viruses. Of the 503 horse blood samples tested, 156 were positive by both AHSV RT-qPCR and VI assays, whereas 135 samples that were VI negative were positive by AHSV RT-qPCR assay. The virus isolates made from the various blood samples included all 9 AHSV serotypes, and there was 100% agreement between the results of conventional serotyping of individual virus isolates by PI assay and AHSV TS RT-qPCR typing results. Results of the current study confirm that the AHSV TS RT-qPCR assays for the identification of individual AHSV serotypes are applicable and practicable and therefore are potentially highly useful and appropriate for virus typing in AHS outbreak situations in endemic or sporadic incursion areas, which can be crucial in determining appropriate and timely vaccination and control strategies.

Identification and characterization of monoclonal antibodies suitable for development of influenza A vaccine seed virus (VAC11P.1101)

Abstract The seed viruses for influenza A vaccine production are high-yield (hy) reassortant viruses generated in embryonated chicken eggs by reassorting wild type (wt) viruses with a hy donor virus, A/Puerto Rico/8/1934 (PR8). Currently, reassortants with wt hemagglutinin (HA) and neuraminidase (NA) are selected for growth by using polyclonal antibodies (pAbs) against PR8. The efficiency and reproducibility of reassortment will be greatly enhanced with monoclonal antibodies (mAbs) which not only provide high specificity against PR8 but could also be prepared as defined reagents with guaranteed activity in unlimited quantities. In this study, from a panel of hybridoma clones prepared against PR8 surface glycoproteins, we found four HA specific mAbs with complete neutralization of PR8 virus in an in vitro plaque inhibition assay, which are designated as mAb-1B3, mAb-1H6, mAb-2A6, and mAb-2D11. All four mAbs have been shown highly specific in both in vitro and in ovo neutralization activity to PR8. Furthermore the epitopes of all four mAbs were mapped to the area around the receptor binding site (RBS) at the membrane-distal tip of HA. Their epitopes are composed of four regions of HA residues 158-172, 183-197, 208-222, and 253-267 (H1 numbering with signal sequence). The HA residues 158-172 and 253-267 are two common regions for all four mAbs, while residues 183-197 is specific for mAb-1H6 and mAb-2A6, and residues 208-222 is specific for mAb-2D11.

In Vitro Evaluation of Synergistic Inhibitory Effects of Neuraminidase Inhibitors and Methylglyoxal Against Influenza Virus Infection

Influenza virus infections are serious public health concerns worldwide that cause considerable mortality and morbidity. Moreover, the emergence of resistance to anti-influenza viral agents underscores the need to develop new anti-influenza viral agents and novel treatment strategies. Recently, we identified anti-influenza viral activity of manuka honey. Therefore, we hypothesized that methylglyoxal (MGO), a key component of manuka honey, may impart anti-influenza viral activity. The aim of this study was to evaluate the anti-influenza viral activity of MGO and its potential in combination treatments with neuraminidase (NA) inhibitors. MDCK cells were used to evaluate anti-influenza viral activity. To evaluate the mechanism of MGO, plaque inhibition assays were performed. The synergistic effects of MGO and viral NA inhibitors were tested. MGO inhibited influenza virus A/WSN/33 replication 50% inhibitory concentration= 240 ± 190 μM; 50% cytotoxic concentration= 1.4 ± 0.4 mM; selective index (SI)= 5.8, which is related to its virucidal effects. Moreover, we found that MGO showed promising activity against various influenza strains. A synergistic effect was observed by a marked increase in SI of NA inhibitors at ∼1/100(th) of their single usage. A synergistic effect of MGO and oseltamivir was also observed against oseltamivir-resistant virus. Our results showed that MGO has potent inhibitory activity against influenza viruses and also enhanced the effect of NA inhibitors. Thus, the co-administration of MGO and NA inhibitors should be considered for treatment of influenza virus infections.

Anti-influenza Viral Effects of Honey In Vitro: Potent High Activity of Manuka Honey

Influenza viruses are a serious threat to human health and cause thousands of deaths annually. Thus, there is an urgent requirement for the development of novel anti-influenza virus drugs. Therefore, the aim of this study was to evaluate the anti-influenza viral activity of honey from various sources. Antiviral activities of honey samples were evaluated using MDCK cells. To elucidate the possible mechanism of action of honey, plaque inhibition assays were used. Synergistic effects of honey with known anti-influenza virus drugs such as zanamivir or oseltamivir were tested. Manuka honey efficiently inhibited influenza virus replication (IC50 = 3.6 ± 1.2 mg/mL; CC50 = 82.3 ± 2.2 mg/mL; selective index = 22.9), which is related to its virucidal effects. In the presence of 3.13 mg/mL manuka honey, the IC50 of zanamivir or oseltamivir was reduced to nearly 1/1000th of their single use. Our results showed that honey, in general, and particularly manuka honey, has potent inhibitory activity against the influenza virus, demonstrating a potential medicinal value.

P2.180 TMR5 (ZedupexTM) as a Management Therapy For Herpes Infections: Results of Preclinical Evaluations

TMR5 (ZedupexTM) is a product of a Kenyan medicinal plant, prepared as a lyophilized extract and a cream. The products have been evaluated for preclinical safety and efficacy in suitable...

Anti-H5N1 virus flavonoids from Capparis sinaica Veill

Methanolic extract of Capparis sinaica Veill was tested for its in vitro antiviral activity against highly pathogenic avian influenza strain H5N1 using plaque inhibition assay in Madin–Darby canine kidney. The results indicated that the extract possessed potent antiviral activity (100% inhibition at the concentration of 1 μg/ml). Based on this result, C. sinaica Veill was selected for further study by applying bioactivity-guided fractionation to isolate its antiviral principles. The fractions eluted with EtOAc and 25% MeOH in EtOAc were found to hold the antiviral activity. Further chromatographic separation of the fractions holding the antiviral activity led to the isolation of quercetin (1), isoquercetin (2) and rutin (3) for the first time from this species. The isolates showed reduction in the virus titre by 68.13%, 79.66% and 73.22% inhibition at a concentration of 1 ng/ml, respectively.

Anti-H5N1 virus metabolites from the Red Sea soft coral, Sinularia candidula

Abstract A novel polyhydroxylated sterol, 3β-25-dihydroxy-4-methyl-5α,8α-epidioxy-2-ketoergost-9-ene ( 1 ) along with three new ceramides, N -[(2 S ,3 R , E )-1,3-dihydroxyhexacos-4-en-2-yl]icosanamide ( 2 ), N -[(2 S ,3 S ,4 R )-1,3,4-trihydroxyhexacosan-2-yl]icosanamide ( 3 ), and ( R )-2′-hydroxy- N -[(2 S ,3 S ,4 R )-1,3,4-trihydroxypentacosan-2-yl] nonadecanamide ( 4 ) were isolated from the Red Sea soft coral, Sinularia candidula. Complete structure elucidation was achieved through extensive spectroscopic analysis including one- and two-dimensional nuclear magnetic resonance spectroscopy. Sinularia candidula extracts of different polarities as well as the isolated pure compounds were screened against the highly pathogenic H5N1 avian influenza strain using the plaque inhibition assay in MDCK. The results indicated that the extracts of the Red Sea soft coral Sinularia candidula possessed potent antiviral activity (100% inhibition at a concentration of 1 μg/mL). The isolates 1 , 2 , 3 , and 4 showed reduction of virus titer by 55.16%, 48.81%, 10.43%, and 15.76% at a concentration of 1 ng/mL, respectively.