Figure 1 - uploaded by Rishya Manikam
Content may be subject to copyright.
Toxicity of inhibitory peptides in vitro . MTS assay for cell viability was performed with increasing concentration of different peptides at different time courses 24, 48, and 72 hours. Results ranged from no evidence of toxicity to less than 10% for different peptides when compared to untreated control. (A) DET1, (B) DET2, (C) DET3, and (D) DET4. Results are expressed as mean from a representative experiment performed in triplicate.
Source publication
Despite the importance of DENV as a human pathogen, there is no specific treatment or protective vaccine. Successful entry into the host cells is necessary for establishing the infection. Recently, the virus entry step has become an attractive therapeutic strategy because it represents a barrier to suppress the onset of the infection. Four putative...
Context in source publication
Context 1
... peptides based on the calculation of the the sum of hydrophobic and charge compatibility index for the receptor/interface against the ligand for all possible sequences of the interface. The antiviral pep- tide sequences were then selected based on the final score, which represented the in silico bonding strength of the receptor-ligand complex. Four antiviral peptide sequences of 10 amino acids that gave the best score for domain III of DENV-2 E protein were selected to test the inhibition of DENV entry and multiplication experimentally. Table 1 shows the amino acid se- quences and final BioMoDroid score of the designed peptides. Toxicity was measured to determine the maxi- mum non-toxic dose of the inhibitory peptides. Be- sides the undesired effect, toxicity could induce cel- lular alterations that decrease the formation of plaques leading to false interpretation of antiviral activity. Toxic effects ranged from no evidence to minimal toxicity for different peptides when com- pared to untreated control cells as shown in Figure 1. Results showed that peptide DET3 has the highest toxic effect compared to other peptides and there were no significant differences in terms of time course of activity (Two-way ANOVA with Bonferroni post-test, P > 0.05). The effectiveness of the designed peptides was verified by testing the antiviral activity of the peptides against DENV-2 using plaque formation assay, RT-qPCR, and Western blot analysis. The antiviral activity analyses were done using the maximal non-toxic dose based on cytotoxicity results of each peptide. In the plaque formation assay, results identi- fied two peptides that were able to inhibit the infec- tion. DET2 and DET4 peptides showed 40.6% ± 24.8 and 84.6% ± 5.6 reduction of plaque formation re- spectively (One-way ANOVA with Dunnett's post-test, P < 0.0001). Results showed no significant reduction of plaque formation in case of DET1 and DET3 (One-way ANOVA with Dunnett's post-test, P > 0.05) as shown in Figure 2. These results were further confirmed by quanti- fication of intracellular viral RNA load using RT-qPCR analysis. Results showed that only DET2 and DET4 significantly reduced the DENV entry and, therefore, reduced viral RNA load. The level of re- duction was 0.29 fold ± 0.16 (28.6% ± 16.3), and 0.81 fold ± 0.07 (81.0% ± 7.0) for DET2 and DET4 respec- tively as shown in Figure 3 (One-way ANOVA with Dunnett's post-test, P < 0.0001). DET1 and DET3 did not show significant inhibition of DENV (One-way ANOVA with Dunnett's post-test, P > 0.05). Western blot results showed a significant reduc- tion of the E-protein quantity in cells treated with DET2 and DET4. The percentage of the reduction was 0.59 fold ± 0.11 (59.1% ± 11.2), and 0.78 fold ± 0.12 (78.3% ± 12.2) for DET2 and DET4 respectively as shown in Figure 4 (One-way ANOVA with Dunnett's post-test, P < 0.0001). DET1 and DET3 did not show significant inhibition of DENV (One-way ANOVA with Dunnett's post-test, P > 0.05). It is clear that the immunoblotting was specific as the membrane incu- bated with dengue immune human serum developed bands (Figure 4C) whereas the membrane incubated with normal human serum did not show any bands (Figure 4B). Furthermore, the bands aligned with the marker at their known molecular weight, namely E-protein of approximately 53 of kDa, NS1 in its di- mer form of approximately 90 kDa, and prM of ap- proximately 21 kDa as shown in Figure 4C. The ability of the designed peptides to inhibit DENV was quan- tified based on the analysis of the E protein densi- tometry readings because this is a structural protein. Dose response curves were generated for the most potent peptides (DET2 and DET4) against DENV-2 as shown in Figure 5. The inhibitory activity increased with increasing concentration of both pep- tides. The DET2 peptide showed a maximum inhibi- tion activity against DENV-2 of 41.5% ± 20.0 at 200 μM with IC 50 above 500 μM (One-way ANOVA with Dunnett's post-test, P = 0.0065), while DET4 peptide showed a maximum inhibition activity against DENV-2 of 84.6% ± 5.6 at 500 μM with IC 50 of 35 μM (One-way ANOVA with Dunnett's post-test, P < 0.0001). The ability of the DET4 peptide to inhibit DENV-2 after the virus entry into the target cells was determined by quantification of intracellular viral RNA load using RT-qPCR analysis. Peptides were added directly to the cells 24 hours post-infection. Peptide DET4 showed no significant inhibitory effect against DENV-2 when added directly to the target cells 24 hours post-infection as shown in Figure 6 (One-way ANOVA with Dunnett's post-test, P = 0.7697). TEM was used to visualize the effect of treatment DENV-2 with DET2 and DET4 on the viral particles surface. The experiment also includes untreated dengue virions as a control. Results showed that the untreated viral control exhibited the normal-smooth outer surface which is typical for all mature fla- viviruses. The surfaces of the virus particles treated with peptides became irregular and had rough edges after treatment with peptides as shown in Figure 7. This may suggest a possible rearrangement of the viral E protein. The search for dengue antivirals is a creative endeavor that is gaining momentum due to both in- creased interest in dengue and substantial progress in the structural biology applications. Since HCV and DENV are members of the same family, Flaviviridae , it is necessary to take advantage of what has been achieved in the drug discovery for HCV and encour- age similar strategies to be adopted for DENV such as using RNAi applications [20, 21] and antiviral pep- tides [22]. DENV entry is a critical step for establishing the infection and a significant inhibition of DENV entry has been achieved by targeting viral entry either using RNAi [23-26] or antiviral peptides [11, 27, 28]. These studies showed that design and synthesis of agents that prevent DENV binding and entry to the cellular receptor sites could prove to be potential antiviral agents for preventing the disease. This study ...
Citations
... Chain A was selected in both structures. The following three regions on the E glycoprotein were selected based on the previous studies with other viruses to be potential binding region (BR) that interact with host proteins, BR1 (residue 305-312, 325, 364, 388 and 390) [33], BR2 (residue 98-109) [34], and BR3 (residue 380-389) [35,36]. On annexin II, residue 268-338 of the domain IV also de ned the interacting region with other viruses [36]. ...
The tissue tropism of a virus is a key determinant of viral pathogenicity which is often modulated by the presence or absence of appropriate molecules on the surface of a host cell that can be used by the virus to gain entry into that cell. Annexin II was seen to interact with dengue virus (DENV) and enhanced infection. Herein, we aimed to explore this interaction as a potential target for the design of anti-DENV therapeutics. We demonstrated annexin II extracellular translocation in Vero cells upon exposure to DENV, extracellular and intracellular colocalization assays as well as co-immunoprecipitation assay were performed to further confirmed protein interaction. Molecular docking and molecular dynamic (MD) simulation were employed to identify the interaction sites. The result showed extracellular translocation of annexin II upon DENV exposure to the cell, the result further showed annexin II colocalizing with DENV E-glycoprotein extracellularly and intracellularly. Furthermore, the result of co-immunoprecipitation assay shows DENV E glycoprotein pulling down annexin II, and the result of molecular docking showed strong interaction between the two proteins. MD simulations has proposed the binding of two regions of annexin II (i) Y274-K280 and (ii) K369-Q327 with BR3 E glycoprotein of DENV2 (residue 380–389), with potential of infections abrogation upon inhibition.
... Chain A was selected in both structures. The following three regions on the E glycoprotein were selected based on the previous studies with other viruses to be potential binding region (BR) that interact with host proteins, BR1 (residue 305-312, 325, 364, 388 and 390) [33], BR2 (residue 98-109) [34], and BR3 (residue 380-389) [35,36]. On annexin II, residue 268-338 of the domain IV also defined the interacting region with other viruses [36]. ...
The tissue tropism of a virus is a key determinant of viral pathogenicity which is often modulated by the presence or absence of appropriate molecules on the surface of a host cell that can be used by the virus to gain entry into that cell. Annexin II was seen to interact with dengue virus (DENV) and enhanced infection. Herein, we aimed to explore this interaction as a potential target for the design of anti-DENV therapeutics. We demonstrated annexin II extracellular translocation in Vero cells upon exposure to DENV, extracellular and intracellular colocalization assays as well as co-immunoprecipitation assay were performed to further confirmed protein interaction. Molecular docking and molecular dynamic (MD) simulation were employed to identify the interaction sites. The result showed extracellular translocation of annexin II upon DENV exposure to the cell, the result further showed annexin II colocalizing with DENV E-glycoprotein extracellularly and intracellularly. Furthermore, the result of co-immunoprecipitation assay shows DENV E glycoprotein pulling down annexin II, and the result of molecular docking showed strong interaction between the two proteins. MD simulations has proposed the binding of two regions of annexin II (i) Y274-K280 and (ii) K369-Q327 with BR3 E glycoprotein of DENV2 (residue 380-389), with potential of infections abrogation upon inhibition.
... Nevertheless, even relatively short motifs of just a few amino acids can be used as powerful tools for applications ranging from regenerative medicine 5 , to drug discovery and delivery 6 and the engineering of smart biomaterials 7 . Currently, many methods for the identification or discovery of biologically active peptide sequences are available, including peptide arrays 8 , in silico modelling to optimize active motifs interpolated from crystal structures or known protein sequences 9 , peptide phage display 10 , or combinations thereof. These can be used to pinpoint the minimal active sequences, i.e., the shortest sequence of amino acids, that are necessary to trigger or inhibit a specific biological function. ...
... In addition, preliminary data presented in two patent filings substantiated that the in vitro antiviral efficacy of peptides, typically effective in the mid-to high-micromolar range, could be significantly enhanced when they were presented in an oligovalent fashion. Examples of this strategy were shown for blocking the entry of IAV, Dengue virus (DENV) 130 and RSV 131 using peptides against hemagglutinin (IAV-HA), envelope protein ectodomain III (DENV-ED3) 9 and fusion protein (RSV-F), respectively. ...
In many applications such as diagnostics and therapy development, small peptide fragments consisting of only a few amino acids are often attractive alternatives to bulky proteins. This is due to factors such as the ease of scalable chemical synthesis and numerous methods for their discovery. One drawback of using peptides is that their activity can often be negatively impacted by the lack of a rigid, 3D stabilizing structure provided by the rest of the protein. In many cases, this can be alleviated by different methods of rational templating onto nanomaterials, which provides additional possibilities to use concepts of multivalence or rational nano-engineering to enhance or even create new types of function or structure. In recent years, nanostructures made from the self-assembly of DNA strands have been used as scaffolds to create functional arrangements of peptides, often leading to greatly enhanced biological activity or new material properties. This review will give an overview of nano-templating approaches based on the combination of DNA nanotechnology and peptides. This will include both bioengineering strategies to control interactions with cells or other biological systems, as well as examples where the combination of DNA and peptides has been leveraged for the rational design of new functional materials.
... For example, Panya et al. (2020) demonstrated the effectiveness of Pep-RTYM derived from the medicinal plant Acacia catechu in inhibiting DENV-2 infections by binding to its E protein, and thus disrupting the interactions between the virus and the host cell receptor (Panya et al., 2020). Another study by Alhoot et al. (2013) demonstrated the ability of the DET4 peptide to inhibit DENV-2 infections (84.6%) by causing structural abnormalities of the DENV-2 E protein, and thus disrupted virus binding and entry into host cells (Alhoot et al., 2013). ...
... For example, Panya et al. (2020) demonstrated the effectiveness of Pep-RTYM derived from the medicinal plant Acacia catechu in inhibiting DENV-2 infections by binding to its E protein, and thus disrupting the interactions between the virus and the host cell receptor (Panya et al., 2020). Another study by Alhoot et al. (2013) demonstrated the ability of the DET4 peptide to inhibit DENV-2 infections (84.6%) by causing structural abnormalities of the DENV-2 E protein, and thus disrupted virus binding and entry into host cells (Alhoot et al., 2013). ...
... It is more advantageous to design antivirals that target viral surface proteins as this could avoid the major difficulty of crossing cellular membranes to reach its target. Various novel therapeutic peptides have been developed based on the DENV E protein and studied for their antiviral activities against DENV (Alhoot et al., 2013;Costin et al., 2010;Hrobowski et al., 2005; of peptides 5F, 5FG, and 5G for 48 h. The MTS assay was used to determine the cytotoxicity of peptides 5F, 5FG, and 5G and the absorbance was measured at 490 nm. ...
Dengue infections pose a critical threat to public health worldwide. Since there are no clinically approved antiviral drugs to treat dengue infections caused by the four dengue virus (DENV) serotypes, there is an urgent need to develop effective antivirals. Peptides are promising antiviral candidates due to their specificity and non-toxic properties. The DENV envelope (E) protein was selected for the design of antiviral peptides due to its importance in receptor binding and viral fusion to the host cell membrane. Twelve novel peptides were designed to mimic regions containing critical amino acid residues of the DENV E protein required for interaction with the host. A total of four peptides were identified to exhibit potent inhibitory effects against at least three or all four DENV serotypes. Peptide 3 demonstrated all three modes of action: cell protection and inhibition of post-infection against all four DENV serotypes, whereas direct virus-inactivating effects were only observed against DENV-2, 3, and 4. Peptide 4 showed good direct virus-inactivating effects against DENV-2 (74.26%) as well as good inhibitions of DENV-1 (80.37%) and DENV-4 (72.22%) during the post-infection stage. Peptide 5 exhibited direct virus-inactivating effects against all four DENV serotypes, albeit at lower inhibition levels against DENV-1 and DENV-3. It also exhibited highly significant inhibition of DENV-4 (89.31%) during post-infection. Truncated peptide 5F which was derived from peptide 5 showed more significant inhibition of DENV-4 (91.58%) during post-infection and good direct virus-inactivating effects against DENV-2 (77.55%) at a lower concentration of 100 μM. Peptide 3 could be considered as the best antiviral candidate for pre- and post-infection treatments of DENV infections in regions with four circulating dengue serotypes. However, if the most predominant dengue serotype for a particular region could be identified, peptides with significantly high antiviral activities against that particular dengue serotype could serve as more suitable antiviral candidates. Thus, peptide 5F serves as a more suitable antiviral candidate for post-infection treatment against DENV-4.
... well 10,11 . In particular, peptide fragments that mimic the binding site of the viral protein on the targeted cellular structure can be used as "decoy" moieties to inhibit the attachment and fusion of virus particles with host cells [12][13][14][15][16] , or potentially serve as tools in analytical investigations of specific virus-host interactions 17 . In the simplest form, these comprise the amino acid sequence in the region of the targeted protein, which is directly involved in the binding interaction with the viral protein. ...
Binding interactions of the spike proteins of the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) to a peptide fragment derived from the human angiotensin converting enzyme 2 (hACE2) receptor are investigated. The peptide is employed as capture moiety in enzyme linked immunosorbent assays (ELISA) and quantitative binding interaction measurements that are based on fluorescence proximity sensing (switchSENSE). In both techniques, the peptide is presented on an oligovalent DNA nanostructure, in order to assess the impact of mono- versus trivalent binding modes. As the analyte, the spike protein and several of its subunits are tested as well as inactivated SARS-CoV-2 and pseudo viruses. While binding of the peptide to the full-length spike protein can be observed, the subunits RBD and S1 do not exhibit binding in the employed concentrations. Variations of the amino acid sequence of the recombinant full-length spike proteins furthermore influence binding behavior. The peptide was coupled to DNA nanostructures that form a geometric complement to the trimeric structure of the spike protein binding sites. An increase in binding strength for trimeric peptide presentation compared to single peptide presentation could be generally observed in ELISA and was quantified in switchSENSE measurements. Binding to inactivated wild type viruses could be shown as well as qualitatively different binding behavior of the Alpha and Beta variants compared to the wild type virus strain in pseudo virus models.
... Adult male (3-4 or 7-8-week-old) and pregnant female (8-12- [83] in Vero E6 and LLC-MK2 cells, respectively. Vero E6 and C6/36 cells are laboratory-adapted cells that have been most frequently used to propagate ZIKV and DENV, respectively, and test antiviral activity [84][85][86][87]. ...
... The reasons for choosing Vero E6 and LLC-MK2 cells, instead of human-derived cells, are that Vero E6 cells are the gold standard for plaque assay to determine the titer of ZIKV stocks, infected cell culture supernatants, and animal tissue homogenates, and plaque assay of DENV has been performed frequently using LLC-MK2 cells [84,87,88]. C6/36 cells can be easily infected with DENV, and produce more virus than LLC-MK2 cells when infected with the same viral titer. ...
Background
Zika virus (ZIKV) and dengue virus (DENV) cause microcephaly and dengue hemorrhagic fever, respectively, leading to severe problems. No effective antiviral agents are approved against infections of these flaviviruses, calling for the need to develop potent therapeutics. We previously identified gossypol as an effective inhibitor against ZIKV and DENV infections, but this compound is toxic and not suitable for in vivo treatment.
Results
In this study, we showed that gossypol derivative ST087010 exhibited potent and broad-spectrum in vitro inhibitory activity against infections of at least ten ZIKV strains isolated from different hosts, time periods, and countries, as well as DENV-1-4 serotypes, and significantly reduced cytotoxicity compared to gossypol. It presented broad-spectrum in vivo protective efficacy, protecting ZIKV-infected Ifnar1−/− mice from lethal challenge, with increased survival and reduced weight loss. Ifnar1−/− mice treated with this gossypol derivative decreased viral titers in various tissues, including the brain and testis, after infection with ZIKV at different human isolates. Moreover, ST087010 potently blocked ZIKV vertical transmission in pregnant Ifnar1−/− mice, preventing ZIKV-caused fetal death, and it was safe for pregnant mice and their pups. It also protected DENV-2-challenged Ifnar1−/− mice against viral replication by reducing the viral titers in the brain, kidney, heart, and sera.
Conclusions
Overall, our data indicate the potential for further development of this gossypol derivative as an effective and safe broad-spectrum therapeutic agent to treat ZIKV and DENV diseases.
... All water and bound ligands found were removed using DSV. A known peptide inhibitor targeting DIII of the E protein was identified from the literature, coded as DET4 (IC50 = 35 μM) [23]. A model of DET4, which is made up of 10 amino acid residues, AGVKDGKLDF, was built using UCSF Chimera Figure 9. Antiviral activity of synthesised short peptide fragments against DENV2 using plaque formation assay. ...
... All water and bound ligands found were removed using DSV. A known peptide inhibitor targeting DIII of the E protein was identified from the literature, coded as DET4 (IC50 = 35 µM) [23]. A model of DET4, which is made up of 10 amino acid residues, AGVKDGKLDF, was built using UCSF Chimera software version 1.11.2 (Resource for Biocomputing, Visualization, and Informatics, CA, USA) [24,25]. ...
... The peptide and virus mixtures were then added to the cells. Infection and plaque assays were carried out as previously mentioned [20,23]. The number of the plaques in the treated samples was counted and plotted as a percentage of plaque formation normalised to the negative control to calculate the inhibition percentage. ...
Data from the World Health Organisation show that the global incidence of dengue infection has risen drastically, with an estimated 400 million cases of dengue infection occurring annually. Despite this worrying trend, there is still no therapeutic treatment available. Herein, we investigated short peptide fragments with a varying total number of amino acid residues (peptide fragments) from previously reported dengue virus type 2 (DENV2) peptide-based inhibitors, DN58wt (GDSYIIIGVEPGQLKENWFKKGSSIGQMF), DN58opt (TWWCFYFCRRHHPFWFFYRHN), DS36wt (LITVNPIVTEKDSPVNIEAE), and DS36opt (RHWEQFYFRRRERKFWLFFW), aided by in silico approaches: peptide–protein molecular docking and 100 ns of molecular dynamics (MD) simulation via molecular mechanics using Poisson–Boltzmann surface area (MMPBSA) and molecular mechanics generalised Born surface area (MMGBSA) methods. A library of 11,699 peptide fragments was generated, subjected to in silico calculation, and the candidates with the excellent binding affinity and shown to be stable in the DI-DIII binding pocket of DENV2 envelope (E) protein were determined. Selected peptides were synthesised using conventional Fmoc solid-phase peptide chemistry, purified by RP-HPLC, and characterised using LCMS. In vitro studies followed, to test for the peptides’ toxicity and efficacy in inhibiting the DENV2 growth cycle. Our studies identified the electrostatic interaction (from free energy calculation) to be the driving stabilising force for the E protein–peptide interactions. Five key E protein residues were also identified that had the most interactions with the peptides: (polar) LYS36, ASN37, and ARG350, and (nonpolar) LEU351 and VAL354; these residues might play crucial roles in the effective binding interactions. One of the peptide fragments, DN58opt_8-13 (PFWFFYRH), showed the best inhibitory activity, at about 63% DENV2 plague reduction, compared with no treatment. This correlates well with the in silico studies in which the peptide possessed the lowest binding energy (−9.0 kcal/mol) and was maintained steadily within the binding pocket of DENV2 E protein during the MD simulations. This study demonstrates the use of computational studies to expand research on lead optimisation of antiviral peptides, thus explaining the inhibitory potential of the designed peptides.
... An increasing number of AVPs are being rationally designed using structural and ligand-based design strategies [28][29][30]. For example, rationally designed, low cytotoxicity AVPs have been created to specifically bind to viral proteins such as protruding glycoproteins and spike proteins to prevent viral-host interactions, interfere with enveloped viral membranes, or inhibit viral proteases [31][32][33]. ...
Viral diseases have contributed significantly to worldwide morbidity and mortality throughout history. Despite the existence of therapeutic treatments for many viral infections, antiviral resistance and the threat posed by novel viruses highlight the need for an increased number of effective therapeutics. In addition to small molecule drugs and biologics, antimicrobial peptides (AMPs) represent an emerging class of potential antiviral therapeutics. While AMPs have traditionally been regarded in the context of their antibacterial activities, many AMPs are now known to be antiviral. These antiviral peptides (AVPs) have been shown to target and perturb viral membrane envelopes and inhibit various stages of the viral life cycle, from preattachment inhibition through viral release from infected host cells. Rational design of AMPs has also proven effective in identifying highly active and specific peptides and can aid in the discovery of lead peptides with high therapeutic selectivity. In this review, we highlight AVPs with strong antiviral activity largely curated from a publicly available AMP database. We then compile the sequences present in our AVP database to generate structural predictions of generic AVP motifs. Finally, we cover the rational design approaches available for AVPs taking into account approaches currently used for the rational design of AMPs.
... It has been known that viral entry is mediated by the viral envelope glycoprotein E which contains structural and functional elements (37). The decrease in the plaque number yield may be due to the alteration of viral E protein arrangement or induction of structural abnormalities through modification of viral membrane protein functions, as previously reported to obstruct the binding and entry of virus into cells (38). Another plausible explanation could be that certain constituents in the extract have competed with the virus for binding into the cells or affected the process of virus internalization (39)(40)(41)(42). ...
... It has been known that viral entry is mediated by the viral envelope glycoprotein E which contains structural and functional elements (37). The decrease in the plaque number yield may be due to the alteration of viral E protein arrangement or induction of structural abnormalities through modification of viral membrane protein functions, as previously reported to obstruct the binding and entry of virus into cells (38). Another plausible explanation could be that certain constituents in the extract have competed with the virus for binding into the cells or affected the process of virus internalization (39- * flavonoids exert inhibitory activities against dengue. ...
In this study, we investigated the antiviral activity of lyophilized crude leaf extracts of the Philippine marshmint (Mentha arvensis L., commonly called yerba buena) against DENV-2 in vitro. The plant specimen was authenticated by DNA barcoding analysis using standard primers for amplification of rbcL, matK, ITS1, ITS2 and trnH-psbA. Aqueous, methanol and ethanol leaf extracts were prepared, and lyophilized prior to testing for its cytotoxicity and antiviral activities. All extracts presented cytotoxic activities against Vero cells in a dose-dependent manner. Half maximal cytotoxicity concentration (CC50) was calculated at 2,889.60 µg/mL for the aqueous extract, 1,928.62 µg/mL for the methanol extract, and 3,380.30 µg/mL for the ethanol extract. Antiviral activities assessed by plaque reduction assay revealed reduced DENV-2 viral infectivity, with the ethanol extract observed to have the strongest activity decreasing plaque numbers by 62% relative to the control. The methanol extract was observed to be most effective when added before infection causing 72% reduction in plaque numbers, whereas none of the extracts inhibited plaque formation by more than 40% when added after infection. DENV-2 NS1 antigen production was significantly reduced by the methanol extract, while viral RNA levels were also decreased as determined by real time RT-PCR. Phytochemical analysis revealed the presence of flavonoids, phenolics, tannins, proteins, reducing sugars and saponins. Our preliminary results are promising, however, it should be interpreted with caution as further studies are needed to establish its potential therapeutic application against dengue infection.
... Hepatitis C virus (HCV) is a single-stranded RNA viruses that belongs to family Flaviviridae (Mohammed et al. 2013;Supanee et al. 2014). Around 150 million people worldwide are chronically infected with HCV and the annual mortality from HCV-related liver diseases reach up to 700,000 individual (Ministry of Health and 2015; World Health Organization 2016; Jefferies et al. 2018). ...
Growing global viral infections have been a serious public health problem in recent years. This current situation emphasizes the importance of developing more therapeutic antiviral compounds. Hepatitis C virus (HCV) and dengue virus (DENV) belong to the Flaviviridae family and are an increasing global health threat. Our previous study reported that the crude venom of Scorpio maurus palmatus possessed anti-HCV and anti-DENV activities in vitro. We report here the characterization of a natural antiviral peptide (scorpion-like peptide Smp76) that prevents HCV and DENV infection. Smp76 was purified from S. m. palmatus venom and contains 76 amino acids with six residues of cysteine. Smp76 antiviral activity was evaluated using a cell culture technique utilizing Huh7it-1, Vero/SLAM, HCV (JFH1, genotype 2a) and DENV (Trinidad 1751, type 2). A potential antiviral activity of Smp76 was detected in culture cells with an approximate IC50 of 0.01 μg/ml. Moreover, Smp76 prevents HCV infection and suppresses secondary infection, by inactivating extra-cellular infectious particles without affecting viral replication. Interestingly, Smp76 is neither toxic nor hemolytic in vitro at a concentration 1000-fold higher than that required for antiviral activity. Conclusively, this report highlights novel anti-HCV and anti-DENV activities of Smp76, which may lay the foundation for developing a new therapeutic intervention against these flaviviruses.
